windows update on an external SSD

[jerwin]

Bootcamp tends to install onto the slowest portions of a fusion drive-- and under certain conditions-- it can be slow as molasses.

So, I installed my copy of windows onto a external SSD. A USB3 drive, in fact/ (Which required me to manually construct the partition map, and do ...other things, since windows doesn't like to be installed to a USB3 drive) When I want to use my specialized CAD program, I hold down down the option key and select the EFI partition.

The problem occurs when I update windows. Somehow, whenever I reboot after an update, the list of available bootable drives is truncated. My external drives, including the all important EFI drive do not show up. And so, when boot into OSX-- and reboot into windows, windows update "knows" that the process has been interrupted, and marks the update process as failed.

Does anybody know what's happening? I have a 2014 imac 5k, with Windows 10 Home, and the usual High Sierra.

 

[crjackson2134]

If you boot into recovery mode, then go to the apple icon at the top left, select startup disk. You will probably find your USB drive there and reboot.

I've had to do that before and it works for me. I don't have anything connected to refresh my memory with so I can't give you exact details, but you should give this a try.

The reason is because the startup drive location is stored in NVRAM and somehow it gets lost at times. I don't why.

 

[whiteonline]

It's possible Windows is aware it is on a USB drive, which will cause a failure. Restarting into MacOS shouldn't cause the upgrade to fail.

Open regedit
Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
Set the value PortableOperatingSystem to 0

Try to update again. Outside of that, perhaps your custom partition map is causing issues? Give it a go....

 

[jerwin]

For the problem of blessing the SSD, I held down option at startup, and then selected the EFI partition with control held down.
For the problem of not seeing the SSD at startup, I directly connected the SSD to my iMac, instead of going through a hub.
For the problem of windows update not working, god only knows. But as soon as I downloaded and ran the windows update troubleshooter, things started to work again and I'm now running the latest version (version 1809, iirc)

thanks all.
https://en.wikipedia.org/wiki/Windows_10_version_history#Version_1809

https://support.microsoft.com/en-us/help/4027322/windows-update-troubleshooter