I posted about this a little while back, and was not able to find a solution. I did think initially it was an Avast issue, but that turned out not to be the case, and since then I have just not used FD-ISR Since that time I have just carried on in my "Main Snapshot" as if I do not have FD-ISR installed, obviously not the ideal solution, but a working one. However now I have got a Win7 disc and I want to install it into a empty snapshot. I have the very first Vista install as a snapshot (Primary), nothing was ever added, installed, or updated in this snapshot and FD-ISR still works fine in here, ie I can create new snapshots, and archive or update from this one. My idea to finally put this to bed was to boot into this, remove the "Main Snapshot" Unfortunately although FD-ISR works fine in this (Primary) it will not remove the "Main Snapshot" This "Main Sanpshot" seems to be holding the whole system to ransom, surely there must be some way to delete it at least. Any and all suggestions welcome.