Sometimes when letters are deleted or filed away and the row for the Review Letter in the database doesn't get updated/removed, a record in the database can be left such that it's pointing to a file that no longer exists (because the actual file has been deleted or moved out of the Reviews folder and in to one of the month folders).
This means that in DMS you will see rows for files that don't actually display - because the file doesn't exist.
There is a utility to fix these:
1. Backup your data first (especially DATA\LETTERS.*).
2. Download: https://www.medilink.com.au/RemoveBlankLetterRecords.zip
3. Unzip to a separate folder and run.