I have an installation of windows 8 on an external hdd. When I try to update to windows 10 the update fails with the message that windows on usb drives cannot be updated. Is there a way to update this portable windows installation?
My laptop came with windows 8 pre-installed. I swapped the drive for an ssd and installed linux which I use mainly. To be able to use windows I followed the instructions given in the answer to this question.
I was not able to update windows on the external drive (the update failed with the message that "windows to go" could not be updated. I then revered the changes in the registry (see linked question). But still I was not able to update - it failed with the same message.
Then I found an additional registry setting in:
I changed the value PortableOperatingSystem from 1 to 0 and the update succeeded.
After the update I had to add the value PortableOperatingSystem, it was removed from the registry. Give it the value "1". Then, shutdown windows (do not use hibernation, press SHIFT while clicking shutdown), remove the drive and mount it with another operating system so you can apply the changes in the linked question (BootDriverFlags 0x14).
After this steps I was able to boot windows 10 from the external drive.