Windows 10: Event log full of VSS 12293 errors and System Restore fails with 0X81000203

Not a Dell problem, but I think I've exhausted the Web and tossed this to Windows community with no solution. Here goes:

 

Dell XPS 8930, Intel Optane+932GBHDD, WDC WD1003FZEX-00MK2A0

Windows 10 Pro v. 2004 Build 19041.508

 

Windows 10: Event log full of VSS 12293 errors and System Restore fails with 0X81000203

 

This has apparently been going on for a long time, but the system shows no external indication of any problems. Nightly backups (Acronis True Image 2021) work, with no errors in the logs.

 

I've tried all of the solutions suggested here and anywhere else I could think to check.

 

Here's all the info and evidence I can think of.

 

Windows 10 Pro v. 2004 Build 19041.508

The C: drive is a factory installed 1TB conventional hard drive with an Intel Optane solid state device.

The and E: drives are partitions on a single 1TB hard drive.

 

VSS services are now set to "Automatic" and are running [Default setting was "manual."]

SFC /scannow shows no problems.

CHKDSK /F of all three drives show no errors.

 

System Restore setting fails with 0X81000203, and the setting and display fields in the System Protection dialog are all grayed out.

 

[The volume mentioned in the VSS errors that I've looked at is always the drive.]

Numerous VSS 12293 errors in Application event log, like this:

 

Log Name:      Application
Source:        VSS
Date:          10/3/2020 8:46:59 AM
Event ID:      12293
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      Dellbox-IV
Description:
Volume Shadow Copy Service error: Error calling a routine on a Shadow Copy Provider {b5946137-7b9f-4925-af80-51abd60b20d5}. Routine details IVssSnapshotProvider::IsVolumeSupported() failed with 0x8000ffff [hr = 0x8000ffff, Catastrophic failure
].

Operation:
   Check If Volume Is Supported by Provider

Context:
   Execution Context: Coordinator
   Provider ID: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Volume Name: \\?\Volume{17319d75-0000-0000-0000-607074000000}\
Event Xml:
http://schemas.microsoft.com/win/2004/08/events/event">
 
   
    12293
    0
    2
    0
    0
    0x80000000000000
   
    110771
   
   
    Application
    Dellbox-IV
   
 
 
    {b5946137-7b9f-4925-af80-51abd60b20d5}
    IVssSnapshotProvider::IsVolumeSupported() failed with 0x8000ffff
    0x8000ffff, Catastrophic failure

   

Operation:
   Check If Volume Is Supported by Provider

Context:
   Execution Context: Coordinator
   Provider ID: {b5946137-7b9f-4925-af80-51abd60b20d5}
   Volume Name: \\?\Volume{17319d75-0000-0000-0000-607074000000}\