Lose data when users cut (move) folders

Recently a user right-clicked on a folder and chose “cut” from the context menu, and then pasted to a new network location (both on the same server, one volume to another). She was doing lots of folders at a time, probably totalling hundreds of megabytes. about 30 files didn’t survive the transfer; what’s more, a user used the “lost” files from the old location for the rest of the evening, saving his AutoCAD work to the old location. Next a.m., the files and old location were gone. Server: NT4 SP6, 256ram, ultra2 drives, 5 gigs of remaining disk space. What happened to our files??