Vista Runs Out of Memory While Copying Large Number of Files
 

It appears that, incredibly, Vista can run out of memory while copying files. ZDNet is reporting that not only does it run out of memory after copying 16,400+ files, but that 'often there is little indication that file copy operations haven't completed correctly.' Apparently a fix was scheduled for SP1 but didn't make it; there is a hotfix that you must request.

http://blogs.zdnet.com/hardware/?p=829