Level 1

9 points

Missing operating system error when installing windows 10 bootcamp to external SSD

I've spent the last 4 days trying to install it, but keep getting a missing operating system error upon restart. The system works fine with the internal hard drive.

I installed windows to an internal partition using a USB stick, then used WinClone to copy the partition data to the external SSD. Then I get this error when trying to boot.

I have no idea where I am going wrong, all of the windows files seems to be on the SSD.

Thanks for your help

iMac, OS X El Capitan (10.11.6), 21.5 inch, late 2012

Posted on Jan 27, 2017 7:18 AM

41 replies

Loner T

Level 9

59,536 points

Jan 29, 2017 8:32 AM in response to aaron-goof

From OS X Terminal, please post the output of

sudo find /Volumes/Bootcamp\ 1 -name "BCD*" -print

There is a space between "\" and "1".

Loner T

Level 9

59,536 points

Jan 29, 2017 8:56 AM in response to aaron-goof

Post the output of

sudo dd if=/dev/rdisk1s2 count=1 2>/dev/null | hexdump -C

Loner T

Level 9

59,536 points

Jan 29, 2017 9:30 AM in response to aaron-goof

Just to confirm, please post the output of

sudo gpt -vv -r show /dev/disk1

Loner T

Level 9

59,536 points

Jan 29, 2017 10:40 AM in response to aaron-goof

The GPT, MBR and NTFS header are correct on the external disk. As a test, if you reboot your Mac with the external disk connected, and hold Alt/Option key, do you see a USB icon with Windows?

aaron-goof Author

Level 1

9 points

Jan 29, 2017 10:42 AM in response to Loner T

Yeah I do, it shows up as a USB icon labelled Windows

Loner T

Level 9

59,536 points

Jan 29, 2017 10:52 AM in response to aaron-goof

You will need to build a W10 installer manually and then run Startup Repair.

aaron-goof Author

Level 1

9 points

Jan 29, 2017 10:54 AM in response to Loner T

Okay will do, thanks for your help. How would I go about doing this?

aaron-goof Author

Level 1

9 points

Jan 29, 2017 1:21 PM in response to Loner T

Thanks for your help, I have successfully loaded up start up repair. However, it cannot find the external SSD. Is there a way around this?

Loner T

Level 9

59,536 points

Jan 29, 2017 3:39 PM in response to aaron-goof

Is there a way for you to connect the SSD to the internal SATA connector physically inside the iMac?

aaron-goof Author

Level 1

9 points

Jan 29, 2017 3:51 PM in response to Loner T

Not that I know of. I have never tried taking it apart, and I don't have any cables to connect it with.

Is there a way to load drivers onto a USB, to select them in the repair utility?

Loner T

Level 9

59,536 points

Jan 31, 2017 7:08 AM in response to aaron-goof

Thanks. Noted for future reference.

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Missing operating system error when installing windows 10 bootcamp to external SSD