Windows 10 Retrospect 17.5.2.103 Pro "Trouble positioning: error -1012 (feature unsupported)" after enabling Hyper-V

[DaveD]

Details in topic header, plus: Windows 10 at latest level. I had to enable Hyper-V. I am running local backup only--no backup clients are configured. This is an older desktop with BIOS, and hyper threading was already enabled in BIOS. Backup is to a 4TB local USB-connected drive.

After enabling Hyper-V, the next night's backup returned hundreds of the above errors, one every 1-2 minutes (email notifications are configured) and I had to manually kill Retrospect the following morning. I manually started the backup today and watched it; it normally backs up and verifies 30GB or so in about 20 minutes. It all worked during the backup but started with the failures during the verify operation, giving a message in the backup window something like "Resynchronizing (this may take a while)" in addition to emailing the 1012 errors. 

A forum search turned up two somewhat relevant topics. The first had to do with Hyper-V forming a separate subnet for virtual machine use, which affected the client. This doesn't appear to fit...

The second, https://www.retrospect.com/en/support/kb/retrospect_virtual_internal_error_1012, involves relicensing to support some changes, but this doesn't seem to quite fit either.

Running an IP scanner turns up a couple new IP addresses that I can't identify, but they are both within my subnet. 

Thanks in advance for any assistance.