I installed Vista sp1 last week and with version 11 every backup is a fullbackup. I updated to the latest version of ATI 11 and same thing. Anyone else have this problem? Been using ATI since version 6.0. Did not change backup parameters; same backup setup I've had for months...just no differentials; everytime it does a full backup. Have WIndows Vista Home Premium. Help! SOLVED: The original full backup was created the MORNING of the day I installed sp1 so all subsequent differential backups were reflecting all of the changes made to the Vista system since sp1 and so were HUGE. I know, duh! The thing that threw me off was that the date of the backup was the day I installed sp1 and so I thought it was done AFTER sp1. Hope this helps others....though not sure anyone else is as stupid as I.