I own Hard Disk Manager 2009 Pro and Backup & Recovery 10 Suite. I have never used the Differential Partition Backup feature as I always create Full Partition images (and always from the WinPE CD). However, I am interested in the Differential Partition Backup, but I wanted to know whether disk defragmentation will cause the program to duplicate sectors which have simply moved due to disk defragmentation. I use Norton 360 v3, which performs disk defragmentation in the background during idle times. Will the program recognize that sectors have simply moved and not back them up again? Also, the last step mentioned on the status screen is "Merge Differential Backup." What is this? I should think the idea is to keep them separate.