I've had the free edition in use for a few weeks now for a client, backing up to an external SSD.
Single drive backup, full image with differentials/increments daily, about 12 Noon.
Needed to do a restore of MS Outlook OST files, however the files don't exist in the expected locations in any of the Paragon full/increment sets.
Does Paragon not backup files that are locked/in use?