I won’t go into great detail here but in short, if VSSAdmin is not letting you delete shadow copies and is throwing this message:

Error: Snapshots were found, but they were outside of your allowed context.  Try removing them with the backup application which created them.

There is another (less safe…) program called DiskShadow which will.

It’s built into windows server… and using it to get rid of pesky shadow copies that won’t otherwise goes away looks like this:

DISKSHADOW> Delete Shadows All

and away they go…

One of the best blog articles I came across that details both VSSADMIN and DiskShadow tool and why VSSAdmin sometimes falls short is here: