I gave someone a copy of my database with 1500 plus records. He installed the latest version of amc, opens the DB and only sees 848 records, nothing more.
There is no really a limit, but the database file might have been corrupted at some point.
You should have a .bak file in the same folder as the .amc file: try renaming that one giving it a .amc extension, and try to open it.
Check also the size of the two files.