vss unable to create shadow copy

This server is a 2012 standard virtual machine hosted on ESXi 5.5.  It fails to backup with Dell Appassure complaining of a problem with the VSS subsystem.

The VM has 3 volumes, and checking the shadow copies tool I found I was able to create shadows on all volumes except the system reserved volume and c:. I then found no shadow storage was associated with the system reserved volume or the c: volume.  I corrected this with vssadmin. Now I have only the C drive unable to create a shadow.

Attempting to create a shadow from the gui tool or from vssadmin creates two errors in the application log. First is event 12289, which complains the device does not recognize the command, followed by event 12297, complaining I/O writes could not be flushed, try again later.  (the server is all but idle)  

The system log also gets and event 10010 which says "The server {1F87137D-0E7C-44D5-8C73-4EFFB68962F2} did not register with DCOM within the required timeout."

I have re-registered the VSS dlls as suggested in several threads even though it works on other volumes.  I have changed the shadowstorage location to another disk, and back again, with no change in status.  

While there are plenty of hits on event 12297, they all pretty much say the same thing.  I am not finding much useful on event 12289. Following is the test of the event.

Volume Shadow Copy Service error: Unexpected error DeviceIoControl(\\?\Volume{3814bfcf-33ee-11e2-93e7-806e6f6e6963} - 00000000000006FC,0x0053c000,00000046A9078EE0,0,00000046A9079EF0,4096,[0]).  hr = 0x80070016, The device does not recognize the command.
.

Operation:
   Executing Asynchronous Operation

Context:
   Current State: calling flush-and-hold IOCTL
   Current State: flush-and-hold writes
   Volume Name: \\?\Volume{3814bfcf-33ee-11e2-93e7-806e6f6e6963}\




Any suggestions out there?