I will skip to the problem, trust me I have to do the copy procedure this way. I am copying files from my Vista 64 system to the external USB 3.0 drive of my shuttle mini pc (XP32), with my adata 32gb usb3.0 stick. None of the PCs have usb 3.0 connections, only 2.0 I copy few folders to the stick from my main (Vista) system and then copy them directly through the shuttle to the external drive (it's a Toshiba drive). For some reason some folders (the same folders) and only them, appeared to not have the same exact size on disk on the external drive from my Vista system. BUT, only them. So, from say 150 folders so far, only the same 20 appear to have this discrepancy. Trying different things I checked the size of the folders on my USB stick and there appears to be the problem. The "change" happens there. But why? First of all the stick is ntfs formated. Second, why these 20 folders and not the all the others? There is nothing I can think of which makes them special. Perhaps I need more sleep but this doesn't make any sense to me. Oh, the size on the stick is a tiny bit larger than on the Vista system. The problem is since these 20 so "enlarged" folders retained their increased size on the external hdd, I can't be 100% for all the rest of the 100s of folders I have to copy, to have been copied correctly or not. I hope I make sense.