Resolved Dual boot CONFIRMED for new Apricorn Velocity DUO X2!!!

Discussion in 'Mac Pro' started by m4v3r1ck, Mar 31, 2014.

  1. pastrychef macrumors 601


    Sep 15, 2006
    New York City, NY
    I had all sorts of trouble with the Velocity Solo in a Mac Pro 3,1. I tried so many things that I honestly can't remember which I ended up using and even then it wasn't an ideal solution.

    On my Mac Pro 5,1, I have no problems booting in to Windows with the card present. The conflicts I experienced were all based on incompatibilities between the 3,1 and the Velocity Solo.
  2. Squuiid macrumors 65816


    Oct 31, 2006
    Thanks for the reply. And does it run in AHCI mode in Windows then? (without hacking)
  3. pastrychef macrumors 601


    Sep 15, 2006
    New York City, NY
    At least on Mac Pros 1,1-5,1, you will have to jump through hoops to get AHCI to working with Bootcamp. I'm not sure about other models of Mac. After weighing my options, I eventually abandoned the idea of attempting to get ACHI working on my Mac Pro. I simply didn't use Windows often enough to justify doing it.
  4. Squuiid macrumors 65816


    Oct 31, 2006
    Wow, really? That makes me think I shouldn't bother with the Duo and just leave the drive in SATA bay 3 instead.

    I thought maybe the fact that it is a Marvell controller might mean Windows would see it as AHCI and not IDE/ATA.:(

    Definitely don't want to hack AHCI as many have done, messy and a PITA!
    Thanks again for your help pastrychef.

    BTW, if you install Windows 10 in UEFI mode you will get AHCI mode. However, the GTX680 won't work. Some other NVIDIA cards do work fine though.
  5. pastrychef, Mar 6, 2016
    Last edited: Mar 7, 2016

    pastrychef macrumors 601


    Sep 15, 2006
    New York City, NY
    I haven't done any reading on installing Windows via UEFI. I have my bootcamp drive installed the conventional method via bootcamp. I usually try to keep things simple to avoid trouble and maintain compatibility. Nowadays, though, I almost never boot in to Windows anymore. I just run my bootcamp drive with VMware Fusion.
  6. Speedmaster 102 macrumors newbie

    Speedmaster 102

    Mar 12, 2016
    Maverick and team - this has been a fantastic read and because of this I am very excited to learn that I can keep using my MP 3.1 with this upgrade. However, I am fully aware that by purchasing the card, I need to install this onto a PC and run BIOS to enable RAID and it has to run in slot #2 on my MP 3.1.

    What I cannot find in this thread is a definite answer, can I boot into OSX and working off of the duo as a raid on my MP 3.1?

    Thank you everyone!
    PS - my english isn't the greatest, I apologize in advance if I do not make any sense.
  7. m4v3r1ck thread starter macrumors 68020


    Nov 2, 2011
    The Netherlands
    Your most welcome Speedmaster!

    I used the DUO x2 in my cMP 3.1 with 2 Samsung 840 EVO SSD's in a Apple Software RAID0:

    1. clean install OS X 10.9 to the RAID0
    2. using Apple Migration Assistant to migrate users/apps/setting etc. from my Carbon Copy Cloner external backup.

    I never tried to make use of the hardware RAID on the card itself, by doing so in a PC. I don't own a PC... :rolleyes:

    PCIe setup I had in my cMP 3.1 (now using a cMP 5.1)
    #1 EVGA GTX-670
    #2 Apricorn Velocity DUO x2 - ASR RAID0
    #3 Nvdia 8800GT Mac Edtion (for bootscreens)
    #4 Caldigit FASTA PRO USB 3.0 / eSATA

    Your English is oke! ;)

  8. jdryyz, May 7, 2016
    Last edited: May 7, 2016

    jdryyz macrumors regular


    Jun 12, 2007
    This is the closest post to what I am trying to accomplish but I'm confused by it.

    If you have a software RAID using two drives with both Mac OS X and Windows, does that mean you successfully partitioned the RAID volume?

    I am someone who used a real PC to configure my two SSDs as RAID0 (see attached). I did it in hardware because I figured it would give the best reliability and compatibility with other operating systems. The Mac OS X side (El Capitan) is working fine but I cannot get my Windows 7 system to work on a separate partition of the RAID. I have tried to restore my Winclone backup from file and an entire drive and both gave me errors. I even tried to just boot directly from my Windows 7 install disk and install to the partition. It formatted it just fine but gave me an error when it actually tried to install. I know that actually using the Bootcamp Assistant won't work here because the PCIe card is "external".

    Anyway, I am wondering now if I need to bother with the hardware RAID based on what you posted. Sounds like the Mac OS X software RAID is just as good and will allow me to have Windows on a partition of the RAID.

    P.S. I had no trouble with Mac OS X and Windows either as a partition of a single drive on port 0 or a separate drive on port 1 that were non-RAID. Of course, I want to take advantage of the increased performance for both operating systems. I'm not concerned about a RAID data loss because I will keep my important working files on another drive.


    Attached Files:

    • RAID.jpg
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  9. m4v3r1ck thread starter macrumors 68020


    Nov 2, 2011
    The Netherlands
    AFAIRC there's NO way you can RAID0 (hardware/software) and use it for both MAC OS X and (bootcamped) Windows.

    Best way is to have 2 DUO x2 cards. You can softRAID0 one for OS X and the other one to have a hardRAID0 using a PC for setting up the RAID0 and port it to the Mac for an install of Windows.

    I could have a chat with my Apricorn Tech-rep for their final confirmation?

  10. h9826790 macrumors G3


    Apr 3, 2014
    Hong Kong
    In my own experence. Software RAID won't work in Windows. It may even cause BSOD if bootcamp driver installed.
  11. jdryyz, May 7, 2016
    Last edited: May 7, 2016

    jdryyz macrumors regular


    Jun 12, 2007
    Darn. That would be a bummer if true.

    I already reported my experience to the Apricorn rep I have been working with in email. In fact, it was he who said partitioning the RAID would be supported. Perhaps he meant one type of OS only. Feel free get a chat response back if it is faster. :D I do not expect to hear back from my guy until Monday.

    I know I will not be getting a second Duo card that is for sure. I would rather wait until the M.2 solutions become more affordable. Of course, I realize they have their share of Windows boot problems also.

    Worse case scenario is I can just devote the RAID to Mac OS X and keep my Windows system as a separate drive in the internal Bay, but that is lot of space for OS X I will not be taking advantage of. 250GB for each is more reasonable.

    --- Post Merged, May 7, 2016 ---
    Okay so software RAID is definitely out. :)

  12. jdryyz, May 8, 2016
    Last edited: May 28, 2016

    jdryyz macrumors regular


    Jun 12, 2007
    Got it working! Bootable Windows and Mac OS X partitions are possible on the Duo with RAID enabled.

    I remembered reading in the thread "Sonnet Tempo Vs. Apricorn Velocity DUO X2"

    where Machines said he did a straight Windows 7 install on a Mac Pro without Bootcamp. So I did my own install test by first doing a clean format of the RAID volume, disconnecting all other drives (internal and external), and then booting from my Windows 7 Pro boot disc. I deleted the existing partition again because I wanted Windows to configure its own (the System Reserved partition and the remaining space divided in half). The installation completed successfully and I was able to boot from it just fine. I didn't bother with Bootcamp drivers because I only wanted to prove the Windows system could boot.

    Of course, when you install Windows this way and then boot back into OS X (I reinserted l my Mavericks drive in the internal bay), the normally invisible System Reserved partition will be visible on the desktop. Again, not a problem for my test.

    The next step was to see if I could restore my Winclone backup to the main Windows partition. It gave me an error saying the volume was not GPT. Of course, because I prepped the entire volume in Windows! Okay, lets just use Disk Utility to clear out what I just did and create two new partitions on a GUID partition map. Done.

    I then decided to use Winclone to restore my Windows drive instead of the Winclone backup file. Restore in progress! Disk Activity is saturating the bus, too! Now before you think this is what made the difference, remember my post above where I said I already tried this.

    The restore completed successfully and I am booting from my full Windows system! My second partition is still there. Can I restore my Mac OS X backup there? Let's try! I attach my El Capitan USB drive and fire up Carbon Copy Cloner. OS X restored and I am able to boot from it! Viola!

    The only thing unusual now is I have Windows as the first partition on the drive instead of Mac OS X. I have never in the history of working with Intel Macs ever done it in this order before because Mac OS X is always installed first, followed by launching Bootcamp Assistant. In this case it does not seem to matter one bit. I also doubt this has anything to do with both partitions working. I am sure if I started over again, I could reverse the order and it would still work. So I really do not know what the problem was to begin with.
  13. pixxelpusher macrumors member


    Aug 1, 2011

    My problems of being able to boot 2 SSD's on my Apricorn Velocity DUO X2 are now fixed. I ended up doing a clean install of Windows 10 in UEFI mode on one SSD, and OS X 10.10.5 on another. Plugged both SSD's to the DUO, restarted and it booted up into OS X fine. I then used BootChamp and selected to boot to Windows, and it did just that! Am now very happy to have both systems running on the DUO, and can easily boot from one to the other. I used Samsung Magician in WIN10 to verify that AHCI mode was working on my Samsung 850 EVO, and also under Device Manager it lists that Standard SATA AHCI controller is being used as the driver for the DUO.
  14. m4v3r1ck thread starter macrumors 68020


    Nov 2, 2011
    The Netherlands
    Congrats and I'm glad that you got it all working well. I'm still very happy with my dual boot Velocity DUO x2 too.

    Enjoy your new setup!!!

  15. Durex macrumors member

    Sep 24, 2009
    @pixxelpusher / and others: I have a 2009 MacPro with 5,1 firmware update and currently going through the process of installing two 500GB Samsung 840 EVO drives to a Apricorn Velocity DUO x2. I wish to have one of the SSD as Mac OS X El Capitan, and the other as Windows 10, and be able to boot either by holding the Option key at boot time. From what I've read, I think this is pretty typical of the setup many folks here have.

    I'm after some guidance on how to install Windows 10 in UEFI mode. Currently there's no operating system installed on the SSDs -- the drives are clean and I'll be installing the OS X and Windows OS's to each drive separately.

    I've found a couple of resources that seem helpful: here and here, but I find some of it a bit vague ("Start Windows Setup in UEFI Mode"...I wonder how exactly that is accomplished compared to starting setup in a non-UEFI mode. Is it required to use a USB drive for the installation of Windows 10?)

    Any pointers from the community would be appreciated! This is an awesome thread which I followed and lead to getting the Velocity DUO x2 + SSDs to make for a simpler and better experience all-round! Hope to get it all completed soon!

  16. Durex macrumors member

    Sep 24, 2009
    I tried to do this:

    but I ended up being able to boot into OS X only. The Windows SSD on the Velocity DUO x2 shows up as "Untitled" in OS X, and will not appear when I hold the "Option" key at boot time.

    Here is what I did, step-by-step:

    1. Create Windows 10 USB boot drive: for install to new 500GB EVO SSD #1.
    2. Create Mac OS X 10.11.6 USB boot drive: for install to new 500GB EVO SSD #2.
    3. I left existing 250GB SSD (dual boot OS X 10.8.5 and Windows 7) in the optical drive bay (may be this was my error?).
    4. Place SSD #1 in drive bay 1 and prepare it in OS X 10.8.5 for Windows 10 install (I had to "initialize" the drive and then followed instructions to make sure the disk has one partition with pure GPT partition and not "hybrid" GPT/MBR disk which prevents Windows 10 from installing).
    5. Boot from Windows 10 USB flash drive and eventually install Windows 10 to SSD #1. I selected the SSD #1 to install to and Windows Setup said it will create some additional partitions (EFI and "System Reserved" I think) but when the install started I encountered the error "we couldn't create a new partition or locate an existing one". I did some reading and used a tool 'diskpart' and followed some instructions which included "clean" and "create partition primary". I started the Win 10 install again, selected the partition, Windows Setup did not say anything about creating additional partitions this time. I thought it was a bit odd. Anyway, I formatted the partition and Windows 10 installed. I am a bit concerned of the "clean" command -- it erased the EFI and System Reserved partitions. But, after install I tested "reboot" into Windows 10 multiple times and this seemed fine. It seemed like the EFI and System Reserved partitions were not needed so I continued. Unfortunately I did not test a complete "shutdown" and cold-boot into Windows 10 (i.e. selecting Windows with "Option" key at boot).
    6. Remove SSD #1 and put SSD #2 in drive bay 1.
    7. Now I removed my existing SSD boot drive (OSX 10.8.5 + Win 7) from the optical drive bay because I wanted to make sure the new OS X would not overwrite or migrate data from that drive.
    8. Boot from Mac OS X USB flash drive and install OS X 10.11.6 on SSD #2. This process goes fine and no problem booting into new OS X 10.11.6 El Capitan.
    9. Remove SSD #2 from drive bay 1.
    10. Now I attach both SSD #1 (Windows 10) and SSD #2 (OS X 10.11.6) to the Apricorn Velocity DUO x2, and plug into slot 3 in the MacPro 4,1 (upgraded to 5,1).
    11. By default the machine boots into OS X 10.11.6. On the desktop I see two drives: "Mac OS" (SSD #2) and "Untitled" (SSD #1, Windows 10). The icons look like "external" drives -- I guess because they are connected via the Apricorn Velocity DUO x2 card.
    12. I shutdown and reboot and hold the "Option" key, but only presented with 2 options: "Mac OS" and the "Recovery 10.11.6" partition.

    I have made at least one mistake in the procedure.

    Possibly I should have installed OS X 10.11.6 to SSD #2 first and left it plugged in, and then installed Windows 10 to SSD #1. Then I could have checked that the "Option" key was able to select which drive to boot when they are both attached to the regular SATA ports. And finally, move both SSD #1 and SSD #2 to the Velocity DUO x2.

    And/Or, I should have taken more note of what the "diskpart" command did when it removed the EFI and System Reserved partitions, which I did not recreate...and I'm not sure the consequence of not creating these...

    What should I do from this point? I'm not sure if I need to, or should, move either or both drives to the backplane and try installing Windows 10 again to SSD #2, or perhaps there's a way to make OS X recognize the SSD #2 as a Windows drive?

    Any help from the experts here would be appreciated! :)

    Thanks folks and sorry for the long post! Just trying to explain the details of what I went through and get the fine points of the procedure worked out!
  17. pastrychef macrumors 601


    Sep 15, 2006
    New York City, NY
    I had a Velocity Solo X2. I wasted a lot of time trying to get Windows to boot from it and was never able to get it to work consistently. At one stretch, I was able to get it to work but, eventually, it stopped working for some unknown reason and I gave up trying. Again, this was after wasting A LOT of time trying.
  18. pixxelpusher macrumors member


    Aug 1, 2011
    It took a lot of trial and error for me as well to get it working and was a really long process, so I'm not entirely sure what the problem would be. I did make some notes which I'll put up, and may help you.

    One thing I would recommend straight up is to remove all PCI hardware you have, and put your SSD's in the internal drive sleds to start with. I just laid my Mac Pro on it's side and had them standing up in the Sata slots, which was fine for the temporary installs / testing.

    Also I would recommend installing your Mac OS SSD first and making sure that all works fine in the internal drive sled.
    Then set up the WIN 10 SSD and make sure that works in the internal drive sled (and plays nice with the OS X SSD and option screen restarts, dual boot etc).

    Then slowly start reintroducing the PCI hardware you have, Still with all SSD's in the internal drive sleds. Launch the WIN 10 SSD and it will now install drivers for your PCI hardware (importantly the Apricorn drivers). It's important I think that the drivers are installed before you move the SSD's to the Velocity Solo X2 PCI card.

    I would then first put the OS X SSD onto the Velocity Solo X2 card, and make sure everything works well and you can still restart both systems properly, and you still get both drives on a option screen restart, dual boot etc.

    Only then, once all that is working I would then move the WIN 10 SSD to the Velocity Solo X2 as well and see that they both work correctly for you in that configuration.

    Also, I think it has been said that you can't have any other versions of Windows installed on your internal drive sleds as they will be selected when you try and restart into Windows 10 from the Velocity Solo X2. I'm not sure if there's a way around this.
  19. pixxelpusher, Jul 25, 2016
    Last edited: Jul 25, 2016

    pixxelpusher macrumors member


    Aug 1, 2011
    Ok here are the things I had written down. I think they are everything I did, so not sure if anything is missing:

    Make The Install USB

    1 - First make a compatible USB installer:

    open Bootcamp Assistant, select the options for "Create a Windows 7 or later version install disk" and "Download the latest Windows support software from Apple."

    2 - You might need to hack Bootcamp Assistant to create the USB:


    ** Problem is Boot Camp will make a MS-DOS FAT32 MBR partition which is bad for UEFI **

    First you need to disable SIP:

    - Restart into Recovery Partition (Command + R)
    - Go to Utilities / Terminal. Enter: csrutil disable
    - (later on to re-enable repeat the steps and enter: csrutil enable)

    Then restart into the OS X system and go into your System Report and find the Boot ROM Version and Model Identifier of your computer.

    Create a backup run: sudo cp /Applications/Utilities/Boot\ Camp\ /Applications/Utilities/Boot\ Camp\

    Then: sudo nano /Applications/Utilities/Boot\ Camp\

    Add your Boot ROM string to:



    Then find the following:



    REMOVE the "Pre" and add your computer as a string, e.g. MacBookPro8,2:
    It should read:



    Save and exit with <Ctrl+X>, Y, <Enter>

    3 - Make sure the USB created by Boot camp is a single partition GUID (GPT). If a Mac Pro finds an MBR, it boots in BIOS/CSM. - this may not be true??

    If you want the PRO version of Win10 you need to add a "ei.cfg" file to the sources directory of the ISO to force it to install the Pro version.

    STEP 1:
    First of all we'll need to extract the content of Windows 10 setup ISO file. You can extract it using 7-Zip. It'll take some time in extracting the whole ISO file.

    STEP 2:
    Now open a text editor and copy/paste following piece of code:


    (When running the installer, if you want a menu to ask you what version to install, leave out the [EditionID] part of the "ei.cfg" file).

    Now save the file with the name "ei.cfg" (make sure it saves as a simple file not a proper text file as that won’t work).

    STEP 3:
    Now copy the "ei.cfg" file and paste it into the Sources folder of Windows 10 setup folder which you got after extracting ISO file using 7-Zip.

    - Also it's important to remove the “bootmgr.exe” file so that there is only the refi one there so it is forced to boot into efi mode (not legacy mbr)

    - Re-create the Windows ISO, and select it in Bootcamp to make the USB.

    **** NOTE: I actually can’t remember if I did it through Boot Camp or did all the ISO editing and made the USB installer as a NTFS / GUID under Windows 7 which I also had *****

    - In Disk Utility format the SSD that you’re going to install WIN 10 onto as GUID / Unallocated Space (it's very important that it is unallocated space and no other format as they won't work properly).

    Now shutdown.

    Remove all other drives and hardware, only leave in the blank Windows SSD drive and the USB installer.

    Restart holding down option.

    - OK that now shows a "EFI Boot" drive on Option screen and worked to get to the installer setup! Also lets you select the version of WIN PRO.

    (If you forgot to delete the SSD drive earlier you can also do it here when you select the SSD drive, click “delete”. It should now say unallocated space and let you continue).

    4 - Then let it install (it may restart a few times).

    5 - Then installing the Bootcamp drivers is optional. I did, but had some problems with the Nvidia / Apple Bluetooth / Realtek drivers in it (caused a crash), so had to remove them from the installer first. I then ran the latest Nvidia and Realtek drivers (WIN 10's Bluetooth drivers seem to work fine as is).

    Also note if you’re running an old Mac Nvidia GT9500 video card, it will never install properly as there are no current drivers for it. Windows will try and download some kind of driver for it but it will crash the system and go into a really bad crash loop that’s almost impossible to get out of. This was a big problem for my initial attempts as you’d need to force updates off first.
  20. Durex macrumors member

    Sep 24, 2009
    @pixxelpusher, @pastrychef: thanks for your replies! There's certainly a lot more to it than meets the eye! I recall the first time I set up dual boot and it was relatively straight, not so much!

    Thanks pixxelpusher for your detailed notes -- there's a lot there even I had not read yet. I will follow the general strategy that you outlined -- it makes sense. My previous drives are all disconnected from the system now, and the only PCI card I have in the graphics card.

    I created the Win 10 USB boot drive from a laptop that was already running Windows 10 Pro 64-bit. When I plugged that USB drive into the Mac Pro it appeared as "EFI Boot" when holding Option key. I will do the Windows 10 install again and see how it goes. It will be a process and probably not work first few times. I hope I can get it soon enough though! I will report back with, I hope, a working procedure!

    Best wishes!
  21. Durex macrumors member

    Sep 24, 2009
    Hello folks! I'm happy to report I got my 2x Samsung 840 EVO's separately running OS X 10.11.6 and Windows 10, with both drives mounted to the Apricorn Velocity Duo x2. Dual boot works perfectly! The Windows 10 Pro install was done in UEFI mode, and AHCI is working in Windows.

    I trashed my disk partitions several times along the way -- sometimes by accident, and sometimes intentional to start from scratch when things went downhill. Getting to a solution was a trial-and-error approach: I started with the simplest procedure and only added complicating steps when it became necessary. I did not use any 3rd party utilities like Rufus or UNetbootin to create boot drives. Furthermore I did not use Apple Boot Camp Assistant, and I did not edit any system files like "Info.plist" or "ei.cfg" to allow Windows 10 Pro to install. It seems I did not encounter the issues that editing those files was designed to resolve.

    The only "complication" I ended up with is that I'm using rEFInd as the boot-loader, which I totally don't mind (it has some neat features, e.g. you can safely reboot/shutdown right from the boot menu, you can customize icons, etc.). rEFInd is the only solution I found that would correctly detect both OS X and Windows boot partitions and list them when I started the Mac.

    One unfortunate item remains but doesn't seem to cause any real problems:
    - When booting into Windows the video signal disappears at the "Welcome screen" and the monitors enter sleep mode. After almost 1 minute the video signal comes back and the monitors turn on. I haven't tested yet if bypassing the Welcome screen and going straight to desktop will eliminate that problem.

    Some websites for background info that I learned from:
    Here's a summary of my final procedure!
    - The objective is a completely clean install of OS X El Capitan 10.11.6 and Windows 10 Pro (UEFI boot with AHCI working) on separate SSDs connected to Apricorn Velocity Duo x2, with dual boot capability.
    - Despite this being a long post, it's not many steps at all and is quite straightforward.

    My Mac:
    - Mac Pro (Early 2009) 4,1 with the 5,1 firmware update
    - 3.46 GHz 6-Core Intel Xeon W3690 CPU
    - 48GB 1333 MHz DDR3 ECC RAM
    - eVGA GTX-680 Classified 4GB (flashed by MacVidCards) - installed in Slot 1
    - Apricorn Velocity Duo x2 PCIe adapter for SATA III - will be installed in Slot 2
    - 2x 500GB Samsung 840 EVO SSDs - will be mounted to Velocity Duo x2 at the end

    - Make sure MacPro4,1 is flashed to the 5,1 boot ROM (MP51.007F.B03). This is essential because MacPro5,1 has updated EFI boot support without which UEFI boot from USB flash drive is not possible.
    - Update Samsung 840 EVOs to the latest firmware (EXT0DB6Q) to address the performance degradation issue on these drives. I did this by creating a boot CD from Samsung's firmware update ISO file. I removed all other drives and PCIe cards and the firmware update didn't have any trouble finding the EVO's to update.
    - Create USB boot disk of OS X 10.11.6 from an existing OS X install using Apple's "createinstallmedia" utility. I used a Mac Mini already running OS X 10.11 to do this.
    - Create USB boot disk of Windows 10 (64-bit) from within existing Windows 7 (64-bit) install. I used Microsoft's Windows 10 "media creation tool" for this.
    - For both USB boot drives I used 16GB USB 2.0 drives.
    - Download Apple Boot Camp Support Package 5.1.5621; this seems to be the last release supporting MacPro4,1 and MacPro5,1. Unzip and copy the files to Windows 10 USB boot drive for install later. I deleted the ATI, nVidia and RealTek folder so these drivers would not be installed automatically. The reason is I read many places that the RealTek and video drivers could lead to a blue screen or other crash during install. Instead I downloaded the latest nVidia drivers and RealTek drivers for manual install later.
    - Remove any non-essential PCIe cards or other HDDs from the system.

    Procedure Summary:
    1. Zero out SSDs
    After multiple failed attempts to get dual boot working, I wasn't sure that simply deleting partitions was going to lead to a completely clean drive and that a previously failed install wasn't going to cause problems for a subsequent install. So I completely wiped the SSDs --- all partitions and any boot information that might be on them.
    - I plugged the two SSDs into the optical drive pay ports.
    - Plug in the Windows 10 USB boot drive.
    - Hold "Option" key for the boot loader. The USB drive will appear as "EFI Boot". Select it and the Windows 10 install will start.
    - At the first "Windows Setup" screen press Shift-F10 to start a command window.
    - References: diskpart and How to wipe a drive and convert to GPT format
    - I then entered commands like this to select and complete erase (zero out -- it takes a while to complete the 'clean all' steps) each SSD:

    list disk
    select disk 0
    clean all
    convert gpt
    select disk 1
    clean all
    convert gpt

    - I closed the Windows Setup window (red X) and shut the Mac down.
    - Disconnect the SSD I will be installing Windows 10 to later.
    - Disconnect the Windows 10 flash drive.

    2. Install OS X 10.11.6
    - Plug in the OS X USB boot drive and power on the Mac. It will boot from the flash drive because there is no operating system present on the SSD that is connected.
    - Use Disk Utility to erase the SSD as Mac OS Extended (Journaled). I'm erasing the whole SSD which will create one partition. I will let the OS X install take care of creating the other partitions (EFI, Recovery) as needed.
    - Finish the OS X install and check that can boot into OS X without problems.
    - Disconnect the Mac OS flash drive.

    3. Install rEFInd
    On earlier attempts I was not successful with the Mac boot-loader retaining correct information about Mac OS and Windows boot partitions: if the Windows system could be found it would appear in the boot-loader as "EFI Boot" instead of "Windows". So I decided to try an alternative boot-loader rEFInd, and installed it before Windows 10.
    - Install rEFInd in OS X "Recovery Mode" (so you don't have to disable SIP) following these instructions, which will install rEFInd to the ESP (EFI System Partition).
    - Reboot and check that the rEFInd boot-loader starts and that you can select OS X and boot correctly.
    - Shutdown the Mac.

    4. Install Windows 10
    - Connect the second SSD. Since the "zeroing out" procedure above this SSD has never been connected to the Mac while running OS X. I made sure not to create any partition on this disk from within OS X. The reason is to avoid any possibility of Mac OS modifying the boot table which prevents Windows from installing.
    - Connect the Windows 10 flash drive.
    - Boot the Mac, and at the rEFInd boot-loader menu there will be an option "fallback bootloader". This is the Windows UEFI boot from USB flash drive. Select it.
    - The Windows 10 install starts. There's no need to do Shift-F10 and do anything with the command window. Just follow the usual Windows install procedure. If you installed Windows 10 previously on the Mac you can skip the product key entry and Windows will automatically activate (using digital entitlement) once setup is completed.
    - When choosing the installation type, select "Custom"
    - When you get to "Where do you want to install windows?" you will see an option e.g. "Drive 0 Unallocated Space" and there being no other partitions on that drive. Simply select the unallocated space. Windows will detect that the system was started in UEFI mode and ensure that the disk remains GPT format. Windows will also create whatever other partitions it needs on the disk.
    - Complete the Windows installation.

    After Window 10 Pro install completed I rebooted a few times and manually installed the graphics (nVidia) and audio drivers (RealTek). I also ran the Apple Boot Camp Drivers installer I copied to my Windows 10 USB flash drive earlier.

    5. Get rEFInd boot-loader back
    At this time I noticed if I shutdown my Mac and turned it on (i.e. "cold boot") the rEFInd boot-loader was no longer appearing and Windows would automatically start. When I pressed "Option" key at boot time Windows OS did not appear in the Mac boot-loader, though Mac OS did appear.

    Something had caused the rEFInd boot-loader to no longer start as expected. I was able to get rEFInd back by booting into Mac OS and re-running a "bless" command that is part of the automated rEFInd installer. See Step 2 (for "mountesp" to mount the ESP where rEFInd is installed) and then Step 8 (for "bless") to re-associate rEFInd as the system boot-loader. Note that you either have to have SIP disabled or boot into Mac Recovery Mode to run "bless".

    After this, rEFInd boot-loader was back and I had a nice interface to select either OS X and Windows 10 Pro. Check the picture attached. The first Windows logo says something like "Windows EFI Boot" and the second says "Legacy Boot" (I didn't try that one yet!)


    I shutdown and restarted the Mac multiple times to check that everything was booting as expected.

    6. Mount SSD drives to Velocity Duo x2.
    - Finally I mounted both SSDs to the Velocity Duo x2.
    - I could/should have tested OS X first on the Duo but I was feeling lucky. :) I strapped both SSDs down and mounted the Duo in Slot 2.
    - Power on the Mac and up came rEFInd with Windows and OS X.
    - Everything boots as expected! :)

    Ultimately, the process is not complicated -- it's just that a lot of care needs to be taken to avoid all the "gotcha's" Potentially the above process can be simplified -- may be rEFInd is not necessary. Anyway, I'm happy to have solved this issue for me, and I hope the above is a good reference for others.

  22. pixxelpusher macrumors member


    Aug 1, 2011
    @Durex congrats on getting it all working!! It does take a while to do, but worth it in the end to have 2 fast SSD's running in the Mac Pro.
  23. Durex macrumors member

    Sep 24, 2009
    Thanks pixxelpusher! I appreciate your support to get it done!
  24. m4v3r1ck thread starter macrumors 68020


    Nov 2, 2011
    The Netherlands
    Wow guys! You're contributing some great additional infos in this thread! Due to some health problems I was not able to answer any questions, sorry about that!

    Thanks to all participants to this thread, very much appreciated!

  25. theunderseaclub macrumors newbie

    May 22, 2008
    Hi guys, just a quick question, there is no way to have a "harddrive" icon for the boot drive when using the Apricorn velcoity Duo X2 right?

    I just got one and loving it, the icon thing isn't a huge issue, but it'd be nice if they weren't the external drive icons.

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