I had a folder named Downloads in the user folder (C:\Users\User). I don't know exactly what I did, but basically I tried to move or copy the folder to an external drive. But the folder was there in the same directory. After I disconnected the external drive the folder dissapeared. After panic, swearing and tears (hadn't yet related with the external drive thing), I created another folder with the same name (Downloads). Then when I connect the external drive again I see two folders with the same name! All my files were in one of them (joy!), but I don't understand what is happening.
I'm using Vista x64, with NTFS.