On Feb. 1st I created a full system clone on external hard disk J, I now would like to back up changes made since I cloned my hard desk. I am dazed and confused!!! Which is better incremental, or differential?? I seem to be missing the BIG PICTURE, incremental, differential. In the Create Backup Wizard, Backup Archive Location: Backup Wizard instructs you to "choose an existing backup file to back up only changes that took place since the backup creation or enter file name for a new full backup." If I choose folder J:\autorun\autorun.inf, files of type: All Files(*) a warning box pops up, that says: "Warning! The file you have chosen is not the Acronis True Image backuo, or the file is corrupted, or this is not the last volume of multi-volume archive. Do you wish to proceed with the current file name? If you proceed, the chosen file will be overwritten and the full backup will be created. Otherwise, you will create an incremental backup by choosing the valid archive file name or the last volume of multi-volume archive." Click tab OK, or Cancel. My external hard drive J\ consists of J\autorun\MyBackup1 thru 11, and New Folder. I have read the Help section and User Guide, and I don't get it. I am missing the BIG PICTURE. I'm dazed and confused!!