Ok. I'm a longtime IT guy but a Mac n00b. My wife just got a 13" MBP and we really like it. I have an external drive that I've been using for Time Machine. When I did the initial time machine setup several weeks ago it said that the computer had around 100GB to back up (lots of photos). It took a while but finally completed. No problems. I looked at the external drive and the amount of disk being used jibed with what I knew it should be using. Fast forward to yesterday. I happened to look at the external drive and instead of 100+GB being used, there was only 14GB on the disk being used. Whoa. I *HAD* stopped a time machine backup earlier in the day because we were doing some things and I didn't want any other processes going on. Could stopping a TM backup (from the TM menu bar menu) cause something like this? I would certainly hope not. It should not have been deleting files at all--we are FAR from using up the entire disk. I manually started a TM backup last night and it backed up ~ 100GB (I watched it's progress in the menu) and all was well. After it completed I went to the drive via the Finder and verified that disk usage was what I should expect. I just cannot figure out how it went from around 100GB used down to 14GB used and then back up to around 100GB. Frankly, it concerns me quite a bit. Does this make any sense to anyone out there?