I created a brand new vault that is about 500GB+. I immediately ran Sanitizer after encryption to check vault integrity (check -vault Z:<vault name>\ -deep). I received “5,490 INFO” in the output text file. They are either EmptyEncryptedFile in the “d” directories or OrphanMFile in the “m” directories.
Theres an option in sanitizer to “deleteorphanMfiles”. Personally i’d just leave them alone, its only INFO not warnings. the M folder is depreciated in 1.5.0+ so the M directory will delete itself after migration to the newer vault format.