Background I have a Mac Pro 1,1 and now that I finally got a new computer (took 5 1/2 years to get it, a rMBP 2.6/16/256) my first ever portable (and 15" is way to small for this legally blind person who sits less then 4 inches from his monitor). My Mac Pro has 250GB Boot, 2x2TB (Secondary drive and RAW Footage) and a 1TB "Primary" drive. I use my Mac Pro as my server (Lion Server) for everything that doesn't need to be on my MBP. I have a Drobo FS exclusively as a Time Machine drive, which had a bad year in 2011 but has been allot better in 2012 until Time Machine gave me headaches. Drobo FS Since this is used exclusively for Time Machine, speed ins't that big a deal since it's just for backup (when Time Machine isn't being a problem which it never used to be). The Drobo has 4x2TB+500GB hard drives The Problem I have a 2TB (1.4TB used) "RAW Footage" drive for videos and decided to move everything out of the sub folder RAW Footage to the drive's top level. Well Time Machine didn't like that and decided to re-backup the all the moved files (1.4TB worth), causing me to run out of space. The Questions Since the files were being moved on the same drive, why would Time Machine need to re-backup the files? I though it would only mark the path change in the backup since it was a file move, not copy? I am going to have to start from scratch, but want to do it right this time. Will running Lion Server be of any help with this Time Machine setup? (The Drobo FS is attached to my AEBS and soon a switch). I really love Time Machines hourly backups so please don't suggest CCC, etc. I want to know what the problem is and now to prevent it in the future.