Hello, I am trying out ATI 11 and am unable to get expected results from a differential backup. GOAL: Folders A, B, C. Full backup of A, B, C once per month and daily differentials of A, B, C on all other days. The full backup has a destination file named Monthly.tib. The dailys have a destination filed named Daily.tib. Both Monthly.tib and Daily.tib exist in the same network folder. Schedule: full backup on the 1st of each month at 2:00a. Daily backup is run daily at 11:00p. For the sake of this test/trial, I have been running them manually. The full backup runs fine with expected results. The daily differential is the same size/data as the full. I have verified/reverified that the daily backup is set up as a differential. I expected the differential to be substantially smaller than the full backup - isn't it supposed to be all changed data since the full was run? Is there an issue with my backup destination files? Both Monthly.tib and Daily.tib exist in the same folder. The folder is a network location. I have exhausted this forum and the documentation for a resolution to this. Acronis technical support has also been unhelpful (with the exception of sending me new code bits to try - build 8027). Thank you, Kevin.