Did you folks ever get any resolution from Acronis on this issue (orphaned snapshots)? We have the same problem, and it is a real paint. Number one, we have not found a simple, consistent way to recover other than do a clone on the current VMDK files to a new machine. There are some other suggestions out there (like powering down the Acronis Appliance, rebooting the host, then trying to create a snapshot/delete all snapshots for the effected vm...others involve running a fixdeletable.py script to correct bad flags left behind by Acronis).
Bottom line is that we now have to very closely monitor our VMs to make sure that we don't run out of storage, which is ridiculous. I agree with Havran...while Acronis tech support is polite, their suggestions for resolution involved only two things:
Download the latest version (I swear that sometime they stall long enough for a version to come out so that they can tell us we need to download)
Delete the entire install and reinstall (and by the way recreate all of the backup jobs).
We have spent hundreds of hours with this product...and I won't say how much money.
We are not a huge install, so if I could find an easy way to recover from the orphaned VMs until Acronis can figure out a way to fix it, I might be persuaded to tough it over for a few more months with close monitoring. Otherwise, it is just not worth our time.
jeff