You might try DiskShadow to create another drive letter, which is actually a shadow copy - then back that up instead.
Here’s my DiskShadow file:
#Make shadows persistent
SET CONTEXT PERSISTENT
SET VERBOSE ON
#Cab location for process
SET METADATA C:\Users\akrabu\backup.cab
#Alias volume with alias
ADD VOLUME C: ALIAS CVOL
#Expose the volume and run command file then unexpose
EXPOSE %CVOL% X:
#Delete the shadow copy
DELETE SHADOWS SET %VSS_SHADOW_SET%
So that basically creates a shadow copy at X:\ then runs the backup script then “unexposes” (deletes) the shadow copy. You would call it by running:
C:\Users\akrabu\.restic\diskshadow.exe -s C:\Users\akrabu\.restic\backup.dsh
Then just make sure your backup script references X:\ (or whatever letter you choose in the .dsh file) instead of C:\
Only hitch I’ve ran into is sometimes DiskShadow won’t unexpose the X:\ and then subsequent backups fail until you notice there’s an X:\ hanging around and manually remove it (and the only way I know to remove it is to delete ALL shadow copies (
diskshadow delete shadows all), which sucks if you actually need other shadow copies to, say, restore a file).
That said, if your VSS is screwed up for whatever reason,
diskshadow delete shadows all is a handy command to reset things back to scratch. Unlike other tools, it really will delete them all - not just the ones it has made itself. Just a pro-tip!