
Using Backup and Restore (Windows 7), I had been unable to “Create a system image” using Windows Insider Program builds going as far back as build 18850. I am currently running Windows 10 Insider Preview Build 18963 (20H1) on a Boot Camp partition on a MacBook Pro (Retina, 15-inch, Mid 2012).
Attempting to Create a system Image would bring up the dialog box, “Where do you want to save the backup” and it would fail with another dialog box with the text:
“Windows could not find backup devices on this computer. The following information might explain why this problem occurred:
(0x81000036)
Close Windows Backup and try again.“
I searched the Windows Insider Feedback Hub, googled the web and Microsoft forums and I didn’t find a solution until a few days ago. On the Feedback Hub, in a post with the title, “Cannot create System Image in build 18956 FIX IT!“, CJH suggested disabling Windows Sandbox and virtual machine.

After disabling Windows Sandbox (Control Panel/Programs/Turn Windows features on or off/Windows Sandbox) I was able to create a system image again. I initially disabled Hyper-V Manager but after re-enabling it, system image still worked.