Hyper-V error: "failed to remove snapshot" when deleting...

Interesting little error I got while attempting to Delete Snapshot Subtree in Hyper-V Manager.  I was able to delete every snapshot, but the first one in my tree which would then throw this error message ('MySnapshot' unable to remove snapshot...).  It did not appear in Event Viewer, just the message window and it appears that (so far) I'm the only one to come across this as there is no mention of it on the blog-o-sphere or internally at Microsoft, so it was a bit difficult to diagnose.  That just goes to show that I must have been doing something really wrong! :-)   In fact I was... the problem was that I accidentally created 2 VMs referencing the same VHD (it would be nice if the 'New Virtual Machine Wizard' would have caught this up front).  Once I fixed this the error message no longer appeared and I was able to delete snapshots freely.

BTW... in case anyone else struggles with what exactly 'Delete Snapshot Subtree' does.  It should probably be renamed to 'Flatten Snapshot Subtree' or 'Merge Snapshot Subtree' because that is exactly what it does... merge and flatten snapshots in the subtree, it doesn't technically delete any of the changes you did in those snapshots, in fact it merges them and flattens them into the parent snapshot or VHD whichever is parent to the snapshot you select when you click 'Delete Snapshot Subtree'.  For example, if you wanted to do the following, then selecting 'Delete Snapshot Subtree' on snapshot1 would merge/flatten all subtree snapshots into the VHD in case you wanted to burn it to DVD or put it on a fileshare... you don't have to include the n# GB of snapshots, just the all-inclusive VHD.