Problems booting on 2020 iMac after cloning internal bootcamp volume to SSD


I just got a new 2020 iMac, and am hoping to be able to use Boot Camp from an external Samsung T7 SSD rather than having to dedicate space on my internal SSD to the Boot Camp volume.

When setting up the Mac, I did a fresh install of Windows using Boot Camp Assistant to an internal partition. That booted up fine, and appears to have all the Boot Camp drivers installed.

I used WinClone 8 to make an image of that to a file, and then used the file to clone it to the external SSD.

However, when I restart and choose the external SSD, the Windows logo briefly loads, but then stops with a screen that gives me an INACCESSIBLE_BOOT_DEVICE error message.

I’ve looked around a bit for other folks who have reported similar problems, but they mostly seem to involve cases of migrating older Boot Camp volumes to newer systems where the drivers are missing or need to be updated.

Does anyone know if and how this can be fixed?


HI, I have the same similar problems to you sometimes it goes straight to a blue screen other times it says there is a problem with it, and another time it kept on spinning but my 2m SSD
the blue light went out. that looked promising but. no such luck.
I have tried everything loads of times and never had any luck getting an external drive to work. Everything thing is good in theory but does not work in practice. It would be nice if you did videos of problems that people have with getting the Bootcamp on an external drive. sometimes it says to inject the drivers? Surly if you clone something it should be the same as the original?When I try. injecting the drivers it fails. I have a 2017 5k iMAC so no T2 chip.

I would say that I would like to get this to work but it looks like I want be able to.If not I will have to go for a. refund. The reason I want it on an external drive is that the internal drive is only 256 I wish I got a bigger drive. I have the OS on an external drive I was hoping I could get Bootcamp on the same drive, but did not know it would only work on the internal drive, I wish there was a cloner like Carbon Copier that did the same for Windows. The other thing is the block size, I would like to copy the Bootcamp to another drive rather than an image. But can,t because of the block size.

for a refund, go here:

Here is what i did. External Sabrent Rocket Nano working fine.
Just got my 2020 5k Imac. Installed windows via Bootcamp seamlessly. Also cloned BC windows onto a Sabrent Rocket ssd external drive.

Did the latter after changing T2 security setting to allow booting from external USB drive. For cloning i used EaseUs Todo. The first clone booted O.K but to my horror there was no sound, no bluetooth and no wifi.

unlike my previous with a late 2015 Imac. Anyway the second try worked. I noticed that when you do a system backup it backs the whole mac ssd drive. The key to success is when you do the recovery to external drive make sure you choose the fat 32 and ntfs files. Do not select the third unknown format file which is essentially the Macos partition. Took me two days to work that one out.
Note Aomei was a non starter