errrm, snapshots were probably turned off in Radiant?! If not, they could be found in maps/snapshots...
Anyway, for future projects, I recommend turning this feature on, it 'saved my life' more than once! You'd just have to clean that folder from time to time
he probably deleted the .map file while cleaning up the snapshots folder like i did on the beggining of my 1st map ,but i didnt put alot in it so redoing it was very easy but annoying (took 30 mins).i just hope he can recover his .map file .tell us if u managed 2 recover it,should be in the unerase wizard (i think thats what it was called)
Happened to me too man. I lost 3 to 5 near completion maps, I lost a map for the TR mod and so many more files I just cant count.
I get into the habit of making everything I can into prefabs, Buildings, rocks, roads, terrain....
Nortons was no help, probly been to long.
Snapshot was not enabled in SDK for some reason. I had it active in my old version of Radiant!
I've learned alot since then so NEXT.