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How to Properly Migrate With a Clean Install to OS X Mountain Lion (From Lion/SL)

Discussion in 'OS X Mountain Lion (10.8)' started by Steve.P.JobsFan, Jul 15, 2012.

  1. Steve.P.JobsFan, Jul 15, 2012
    Last edited: Aug 6, 2012

    macrumors 6502a


    Hello, all!

    Since there was a big fury last July on how "hard" it was to do a clean install of OS X Lion, I made a little 4 page PDF on how to do a proper clean install of Mountain Lion, when upgrading from OS X Lion. This puppy took me 2 and 1/2 hours to write, and get looking nice, and to make it easy to understand. I thought this might help some people out. Since the nice people on this forum have been so nice, courteuous, and saved me from many headaches and from filling out many loan forms at the bank, this is my (little) gift to you all. It's attached to this post. Enjoy! :p

    If you find any errors in this document, please let me know. I will work quickly to resolve the error(s).

    This guide is also compatible with Users/Developers running Mac OS X Snow Leopard.

    I will soon be releasing another guide on how to apply incremental OS X updates to your USB flash drive. So, you can have 10.8.1, or 10.8.2, or 10.8.3, etc. on your USB flash drive, instead of stock OS X 10.8. That way, you don't spend your entire day installing combo updates once you reinstall. This guide will be out soon. I'm estimating no later than 48 hours after Mountain Lion is launched, OR the first incremental update to OS X 10.8 is released.

    EDIT1: Fixed an error causing trademark information to be displayed on all pages. Please re-download the PDF, so you have the most up-to-date version. My apologies for the inconvenience.

    EDIT2: Fixed multiple grammar issues, and placement of the trademark text box. Please re-download the PDF, so you have the most up-to-date version. My apologies for the inconvenience.

    EDIT3: Included warning that users who backup to a Time Capsule cannot boot into their backups, and must skip the step, but should verify they have multiple backups of their Mac on the Time Capsule. Please re-download the PDF, so you have the most up-to-date version. My apologies for the inconvenience.

    EDIT4: Re-wrote step 3, backing up your data. Since you can no longer boot to your Time Machine backups as of OS X 10.7.3, I have changed the recommendation to making sure you have multiple backups of your Mac. Please re-download the PDF, so you have the most up-to-date version. My apologies for the inconvenience.

    EDIT5: Included notification that users should deselect all options from the "Settings" drop-down menu in the OS X Migration Assistant. Included information for Mac OS X Snow Leopard users. I strongly encourage all users of this guide to re-download the PDF, so you have the most up-to-date version, with all warnings and system requirements. My apologies for the inconvenience.

    EDIT6: As per many requests, I have added detailed images on how to mount the "InstallESD.dmg" in the Finder, how to restore the image to your USB flash drive, and how to wipe your Mac's internal hard drive. Please re-download the PDF, so you have the correct version. However, please note that the new PDF with these changes is currently in an "experimental" status. I'm so fatigued, I cannot tell if the instructions make sense. If they don't please notify me. I will resolve it in the morning, and merge the PDFs together. Thank you!

    Attached Files:

  2. macrumors 6502

    You, sir, are amazing. I believe I speak on everyone's behalf when I say THANK YOU. 
  3. Steve.P.JobsFan, Jul 15, 2012
    Last edited: Jul 16, 2012

    macrumors 6502a


    You're welcome!


    I have fixed a few more errors in the PDF. See "EDIT2" in the original post above for more details. Please re-download the PDF, so you have the correct version.


    If an administrator of the MacRumors Forums is viewing this thread, I think a lot of people (including myself), would appreciate it if you could place a sticky on this thread. That way, if somebody does encounter an issue with migration to OS X Mountain Lion, they can quickly refer to my document. This may save plenty of headaches, and will cause less threads to be created regarding Migration to Mountain Lion. This will save you disk space on your server. Again, I'd appreciate it if you could sticky this thread. Thank you.
  4. macrumors 6502a

    Very good manual on how to perform a "clean install". Of course by migrating data, applications, etc. from a Time Machine backup you are negating the "clean" in "clean install":)

    I was wondering; you talk about "...then boot from your Time Machine backup." First of all, when I do this on my MBP I see the Master and the Recovery HD. I can select a Network, but I never see my Time Capsule. Secondly, even if I did see my TC, how would I boot from it? I could restore it, after for instance reinstalling OSX from the Recovery HD, but I don't think you can boot from your TC.

  5. Steve.P.JobsFan, Jul 16, 2012
    Last edited: Jul 16, 2012

    macrumors 6502a


    Well, when I do a TM restore, I uncheck the "settings" box. Then it's practically a clean install. No system settings from 10.7 are copied. Just user data. I didn't recommend that option, because users may not like re-configuring all their system settings. But it's still a clean install, as all remnants of OS X 10.7 are gone.

    Now, here's what's up with the Time Machine backup. If you do a backup to a USB, FireWire, or Thunderbolt drive, without excluding anything from the backup (see photo below), OS X will make it a bootable backup, it will create a version of the OS X Recovery partition on your Mac on your Time Machine drive. That meaning, if you screw the pooch (excuse the clichè expression), you can tell your Mac to boot into the Time Machine drive, and it will boot into a version of the Recovery partition that's on the Time Machine drive, to restore your Machine.


    In regards to booting from your Time Capsule backups, I'm not completely sure, as I don't own a Time Capsule. I will do a little more digging, and try and find an answer for you. If you cannot boot to your backup, then I will edit the PDF, and you can skip the step. Just make sure you have a couple of backups on your Time Capsule, though.
  6. Steve.P.JobsFan, Jul 16, 2012
    Last edited: Jul 16, 2012

    macrumors 6502a


    I have fixed a few more errors in the PDF. See "EDIT3" in the original post above for more details. Time Capsule Users, Please re-download the PDF, so you have the correct version.
  7. macrumors member

    This is informative and helpful - can I ask if someone could clarify a couple of things - apologies if they are basic questions.

    When I transfer my data back onto the Mac presumably this includes my installed applications? What I mean is it wont trigger Microsoft Office or Adobe Photoshop to consider it to be a new activation, and therefore refuse because the number of licences or installations has been exceeded?

    Secondly - I've read the comments about excluding system files, but will this mean that you lose library components such as application support?

    Previously I've always upgraded from Tiger to Leopard etc rather than do fresh installations - am a bit wary about doing a fresh install if it means I lose important supporting files or if it triggers problems with existing applications.

    Thanks in advance for any responses
  8. macrumors 6502

    Thanks dude :)
    I'm using the GM version of Mountain Lion and I didn't do the clean install from Lion. Should I proceed with the same steps upgrading from my GM version to Retail version as is for Lion?
  9. macrumors 6502a


    Ello, Duncan! (Excuse the shotty attempt to be a Brit...)

    When you transfer your data back onto your Mac, your apps will be transferred too, because the Applications folder is a system directory. So, your apps will be transferred. Now, when I've done clean installs, I've had mixed results with triggering an application's activation wizard. With MS Office for Mac 2008 & 2011, I haven't had it reset the activation. Out of 6 clean installs of Lion in the past year, it's only asked for my key again once. I also have Photoshop, but I have PS Elements. Photoshop asked me for my key every fresh install. However, I excluded the all the System files, including the Application Support folder, etc. My recommendation to you is that you deactivate your license in Photoshop before doing a clean install. Below is a link to a help article on Adobe's site on how to deactivate Photoshop. The instructions are for Photoshop on Windows, but it should be the same for OS X. With Microsoft Office, it'll be fine. Just be sure to deactivate Photoshop, just to be safe.

    Activation, deactivation | Adobe products


    I don't see why these instructions wouldn't work on the Mountain Lion GM. As long as you can use disk utility to copy that image to a USB flash drive, and boot to your iMac's internal recovery partition, and format your internal drive, you should be good to go.
  10. macrumors 6502

    Ok, I'll see when the time comes xD
  11. macrumors 6502


    Not that I've ever tried but I've always been led to believe that a Time Machine backup isn't bootable.

  12. macrumors 6502a


    When you boot from a TM backup disk, you'll just boot into a TM version of the Lion Recovery HD. The reason I recommend booting from your TM backup, is to make sure you have a way to restore your Mac, in the unlikely event something goes wrong. See the photos below for what happens when you boot from a TM backup.

    Now, I just tried to boot into my TM backup. I wasn't listed as a valid boot device. I did a lot of digging, and found out it you could boot to a TM drive in OS X 10.7, 10.7.1, and 10.7.2, but once you get up to 10.7.3, you can't anymore. I wasn't aware of this change, and I'll be removing the steps from the PDF. Thank you for making me aware of this issue.


    I have fixed a few more errors in the PDF. See "EDIT4" in the original post above for more details. Please re-download the PDF, so you have the correct version. My apologies for the inconvenience.
  13. macrumors 6502

    Think this is a really comprehensive guide and I know backing up your data should be a given, but I think it should probably be added just in case some people follow this without realising that it will actually erase their bootable Macintosh drive. Maybe just an additional step in the Preparation section and then a big warning around step 13/14.

    Would be something Apple would be proud of then ;)
  14. macrumors 6502a


    What do you mean, I should add backing up data to the PDF? It's already i there. As for a big warning around step 13/14, I might just do that. Thanks for the suggestion.
  15. macrumors regular

    Thank you for this ... Definitely will be helpful next week
  16. macrumors regular

    Difference between a Flash disk clean install and DVD ?

    Hi All,

    The question may be a no-brainer but I'm still posting because in the past I have only used DVDs to do clean installs, all the way from Leopard to Lion.

    As such I haven't used a flash disk before. I would like to know if a Flash Disk clean install will be reliable ? I'm a little extra careful and its caused by the years of frequent usage of DVDs to do installation of new OSX.

    The post written by "Steve.P.JobsFan" is excellent and I thank you for that.
  17. macrumors demi-god


    They are reliable and many users here have used USB keys to do installs with no problems. If the USB key is defective, it would normally show up as an error when you are creating the installer.
  18. macrumors 604


    Flash is actually more reliable. DVDs can be scratched and build up dust. Flash drives are a little more durable than that. The only thing would be to remember that the flash drive is designated as the OS Install Disc and not use it for some other purpose.
  19. macrumors 6502a


    They are totally reliable. Just like other users, I would say they're more reliable. I've done almost 10 installs of OS X Lion with my 8GB Flash Disk, and it's much more reliable. Also, don't forget that USB has a higher read/write speed than an optical disc. It installs in 10 minutes.


    I've added more information to the main post.

    I'll be creating a guide on how to update your USB flash drive. So, when OS X 10.8.1 is released, you can put 10.8.1 on your USB flash drive. Then, you can also update with OS X 10.8.2, 10.8.3, 10.8.4, etc.
  20. macrumors regular

    That will be great ! Thanks for the answer. You are doing a great job !
  21. werlingdervish, Jul 21, 2012
    Last edited: Jul 21, 2012

    macrumors newbie

    Variation on clean install for new Macs less than 1 year old

    This is what I did with my newer Mac that came bundled with the Recovery HD partition on the internal hard drive. I used migration assistant as setup assistant is not available on this Lion machine.

    It took me four easy steps on a new iMac (any Mac shipped with Lion) to clean re-install a new OS and recover files.

    1) Hold the option key on a restart of the computer and launch the small Recovery HD ( recovery OS with utilities) in its well protected partition on the hard drive.

    2) Go to the disk utility option presented to erase/reformat the internal hard drive, i.e. actually it only erases the main partition with its previous incarnation of your full OS and user files that are presumably now buggy, corrupted or other wise compromised.

    3) Go next to the Reinstall Mac OSX option. After OKing the internet download, the Apple servers automatically verify you registered computer's eligibility for a Lion OS Download. Download time for the full Lion OS was 40 minutes over cable. [If you are upgrading to Mountain Lion I am not sure if this will take you directly to it. I would definitely make your online purchase of any Mountain upgrade before doing any HD Recovery -- it MAY facilitate a direct download of your purchased OS within Recovery otherwise you will have to go to the app store to re-download an upgraded OS]

    4) Now restart you Mac selecting the main internal drive as startup and move back in your user files and fresh install your apps. Since I had multiple user accounts with many docs and multiple picture and audio files on this iMac, I still used migration assistant to bring over the user files form the Time Machine backup. But, by unchecking the migration of applications, system config files and "other" files I got a new install that was clean enough for me, sans orphan apps going back to PowerPC days and other crud in the application support and "Other" folders. iMac performance markedly improved. Took me an hour to migrate 200 GB in files with a thunderbolt drive.

    A note of interest is that I could easily manually copy over my old iWeb application directly from a date specific backup folder on my Time machine drive-- the webpages and domain came over with the user files migration. [I temporarily did NOT OK use of the backup drive as my new time machine backup until these selected old apps or files were manually moved] I was also able to view, search-find and copy over specific .dmg installer files directly from date stamped backup folders as I felt they were clean enough for installing recent download purchases of FilemakerPro etc. And, I re-downloaded purchased apps from the App store.

    Whatever you do AVOID the Time Machine recovery option in HD Recovery as it simply reloads your HD with ALL the old and/or recently corrupted files. There are no selective options as in migration assistant and no escaping a 2 hour wait of reloading old and corrupt files.
  22. macrumors 6502

    Just posting to say thanks for taking the time to make this!

    Downloaded the guide, it will be a big help!

    Thanks :)
  23. macrumors 6502a



    Your iMac does have Setup Assistant. You know how when you install OS X, and it asks you to setup your language, keyboard settings, create an account, etc? Apple calls the program that asks you to do all of that "Setup Assistant."

    I know you can boot into Recovery, and download the OS from there. However, People have had previous issues on wiping their Mac's HD. My process is three steps.

    1) Download OS X Mountain Lion from the Mac App Store.

    2) Flash the DMG to a USB flash drive.

    3) Boot from the USB flash drive. Wipe the Macintosh HD, and install Mountain Lion.


    However, I spread those 3 steps out over multiple pages. Why? To make things easy to understand.
  24. macrumors member

    Thanks for the guide!

    I'm just wondering, if I do not want to go through the hassle of buying a new USB drive... would it be possible if I just press command-option-R and use Internet recovery option (without pre-wipe my current harddisk) to clean install Mountain Lion after it's released?
  25. macrumors 6502

    Nice topic! Just what I needed.

    I need help, please!

    I was trying to do a clean install of ML on my MacBook 5,1 (late 2008) and when I boot it up from an external HDD it goes straight to the part where it tries to install the OS X (that big window with the big X and the progress bar on the bottom).

    It stays there for a few seconds and then I get the following message:

    "There was a problem installing "Mac OS X".

    Try reinstalling."

    I rebooted already a dozen times. Used the Disk Utility to verify both the HDD where ML will be installed (which as been correctly formatted and is now empty) and the attached external HDD which contains the installation dmg of ML.

    I'm out of ideas now. What the hell is going on?

    My MacBook 5,1 supports ML, right?

    I checked the dmg installation file of ML before and it check out in Disk Utility.

    Hope someone can help! Thanks a bunch!

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