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iMac not booting from USB

F

Freeks

macrumors regular
Original poster
Jul 2, 2009
176
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I just got latest iMac and tried boot from my old laptop ssd via USB dock and all i get is grey screen with error sign. Same ssd boots just fine with two laptops, but not with iMac.

I tried also boot from usb installer but get same error. Any ideas? I have never seen that error before.
 

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Freeks said:
I just got latest iMac and tried boot from my old laptop ssd via USB dock and all i get is grey screen with error sign. Same ssd boots just fine with two laptops, but not with iMac.

I tried also boot from usb installer but get same error. Any ideas? I have never seen that error before.
Click to expand...
Booting from an external device ( such as USB stick ) will trigger the password prompt if the iMac's firmware password is set but your screen shot doesn't show that prompt. Have you tried booting with the OPTION key held down? Presumably results will be the same but if it shows boot drives it could be a clue.
 
Freeks said:
I just got latest iMac and tried boot from my old laptop ssd via USB dock and all i get is grey screen with error sign. Same ssd boots just fine with two laptops, but not with iMac.

I tried also boot from usb installer but get same error. Any ideas? I have never seen that error before.
Click to expand...
The minimum OS that will run the "latest iMac" is El Capitan (10.11). If the OS on your external old laptop ssd via USB dock or USB installer is earlier then 10.11 then it can not boot your new iMac.
 
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Thanks for the replies!
OS in SSD is 10.11 same as in iMac. If i boot with option-key i can see the ssd as boot option, but when i click it i get that error screen. It never advances to the point where password is entered.

It does the same with 10.11 installer USB stick. So i could not even do clean install if i wanted.
 
Something to try:

Clone the contents of the non-booting USB flash drive to ANOTHER flash drive using either CarbonCopyCloner or SuperDuper.

See if the SECOND flash drive does the same as the first..
(i.e., eliminate the physical flash drive as "the problem")

Another (possible) workaround:
You'll need an external drive.
Using a DIFFERENT Mac, do a "clean install" of the OS onto an empty drive.
Boot from the new install, set it up with a temporary account.
Put CarbonCopyCloner onto the drive, as well.
Now, connect it to the iMac.
Will it boot?
If it does, ERASE the iMac's internal drive and (again) use CarbonCopyCloner to clone the contents of the external drive to the iMac's internal drive...
 
CoastalOR said:
Has the old laptop ssd via USB dock and/or the usb installer successfully booted another Mac?
Click to expand...
yes it works with old MBP 2008.
[doublepost=1487094486][/doublepost]
Fishrrman said:
Something to try:

Clone the contents of the non-booting USB flash drive to ANOTHER flash drive using either CarbonCopyCloner or SuperDuper.
Click to expand...
I have USB drive so i will try to copy that drive. But as the USB stick didn't work i don't think it will work with another USB drive. Let's see after SuperDuper copies and i can try it...
 
So i cloned the SSD to USB drive with CCC, but it's still no go. I can choose to boot from it, but it boots to error screen. I know now it's not the boot HW. It's something wrong with the iMac.

Have anyone else had this error?
 
In your original post, you said it was "the latest" iMac -- which I'll assume is a late-2015.

Will it boot at all?
From any source?
 
Fishrrman said:
In your original post, you said it was "the latest" iMac -- which I'll assume is a late-2015.

Will it boot at all?
From any source?
Click to expand...
Yes, it's 2015 latest iMac.

I bought new Seagate USB3 drive and clone the boot disk and it don't work. Same problem with all drives with that backup. I probably need to contact Apple and ask why this iMac can't boot 10.10 backup drive.

I will do test and clone internal 512GB SSD to the new USB Drive and try if that boots.
 
nambuccaheadsau said:
It can't because it cannot find drivers. As a rule of thumb no going backwards from the OS the iMac was released with.
Click to expand...

Not the case here. Same drives boots in 2015 Macbook. It's also same OS version. But as soon as i get the internal SSD cloned i can see if that's the case. Internal SSD is pretty damn fast! So cloning to new USB3 drive goes quite fast.
 
Freeks said:
Yes, it's 2015 latest iMac.

I bought new Seagate USB3 drive and clone the boot disk and it don't work. Same problem with all drives with that backup. I probably need to contact Apple and ask why this iMac can't boot 10.10 backup drive.

I will do test and clone internal 512GB SSD to the new USB Drive and try if that boots.
Click to expand...
The 2015 iMac can't boot Yosemite (10.10), so don't bother to waste your time asking Apple. I say again, as I said in post #4, the lowest OS is El Capitan (10.11). I realize in your post #6 you said OS 10.11, but on post #12 you said 10.10. The misinformation leads to a lot of confusion.
 
Sor
CoastalOR said:
The 2015 iMac can't boot Yosemite (10.10), so don't bother to waste your time asking Apple. I say again, as I said in post #4, the lowest OS is El Capitan (10.11). I realize in your post #6 you said OS 10.11, but on post #12 you said 10.10. The misinformation leads to a lot of confusion.
Click to expand...
Sorry it was my typo. I meant 10.11.

But did try to clone internal SSD and boot from that and it worked. Workaround is to ditch this iMac and get iMac that can boot that drive. I have migrated from mac to mac since 2006 and this time i wanted fresh start. I don't want install everything i had on laptop. But i have several projects that will not open properly in imac.
 
OP wrote:
"But did try to clone internal SSD and boot from that and it worked. Workaround is to ditch this iMac and get iMac that can boot that drive"

Hmmm....
You're saying above that you HAVE a copy of the OS which WILL boot the iMac in question?

If so, then USE WHAT WORKS.
Stop trying to boot with copies of the OS that DON'T work...
 
Freeks said:
But did try to clone internal SSD and boot from that and it worked. Workaround is to ditch this iMac and get iMac that can boot that drive. I have migrated from mac to mac since 2006 and this time i wanted fresh start. I don't want install everything i had on laptop. But i have several projects that will not open properly in imac.
Click to expand...
Let's see if I understand. You have a external USB drive that is a clone of your 2008 MBP running 10.11.6. You want to use the USB clone to boot your iMac so you can run your projects without having to install the apps/projects on your new clean iMac.

If I am correct in my understanding then you could try booting from your working cloned iMac external drive, connect the clone of your 2008 MBP, run the Migration Assistant app to migrate the apps/files etc. to the iMac clone. That might work to give you external bootable drive with the apps and projects you need without installing them on your new iMac.
 
I'm having a similar problem with a recently-purchased mid-2011 iMac 2.5. I killed the OS in trying to load Peppermint Linux onto a separate partition, and now it boots to a blinking question mark. A chat with Apple help folks promoted me to erase the hard drive (which went fine) and attempt an internet recovery, which took me to Apple's online applications store, but would not recognize my login (which I can access from another Mac just fine).

It seemed time to reflash 10.13 onto my erased iMac. An IT-savvier friend downloaded and burned the 10.13 DMG to a USB, but when I insert it and boot holding the option button, no bootable media is found.

Here's what I've tried since:
  • Performed SMC and PRAM resets per https://discussions.apple.com/thread/4035547; no change.
  • Ran the hardware test (booting while pressing the D key), no problems found.
  • Tried booting with the thumb drive in a different USB port; no change.
  • Inserted a 10.6 boot DVD (left over from a 2006 iMac); it will (but I've not actually booted from it).
Can anyone out there guide the owner of a glass-and-aluminum paperweight in the shape of a 2011 iMac?
 
Have you checked the volume format (NTFS, FAT, HFS+...)? Not sure if you can start macOS on a FAT32 formatted USB drive...
 
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