If you're renaming a file in Windows Explorer and you accidentally hit the forward slash rather than the full stop you get a Tooltip prompt reminding you that you can't use certain special characters in filenames. Earlier today I was in a folder which contained another folder named "Stuff" and a rar archive I'd just created called "Stuff.rar". I was editing the filename of the archive to add in today's date and I accidentally entered "Stuff 2009 02 06/rar" (i.e. there was a forward slash rather than a full stop (period)). When I hit enter my RAR file now appeared as a folder named "Stuff 2009 02 06" and inside it was a file named "rar". I did a bit more experimentation after this. If I just renamed the Stuff.rar file to Stuff/rar then the "rar" file appeared inside the original Stuff directory.
Has anyone else seen this problem before? It's a bit difficult to search for, so apologies if it's a repost...