Backup type seems to have changed on its own!
I have been using ATI2019 successfully for some years backing up my 'E:' data disk to an external USB3-connected 1TB drive. It is setup to do a differential backup with several versions before a new full version. I do this backup approx monthly and have an earlier backup set complete and I am halfway through my current set.
I've just done my normal monthly backup. It completed successfully but reports that it is an incremental backup whereas all the previous backups are actually differential. This latest backup .tib file is also really small at 19MB whereas previous differential versions are typically 15GB.
To my knowledge I myself haven't changed the backup method - it's been differential for some time. Indeed I'm well aware that one shouldn't simply edit this setting but should copy a version first before editing the backup method. I haven't verified this latest backup yet. I don't want to re-run Acronis at this stage!
What should I do? I'm inclined to copy the settings, revert to differential, rename it and start a complete new backup series. But I'd be happy to help diagnose what has happened here, if that is possible.