I had a client call me with a "FPT file is either missing or invalid" error during the reindex process. When I received the backup I could open the file to read the memo fields, append records, and delete records without the error. The error only occurs when issuing a PACK. I fixed the problem by creating a cursor to hold the data, zapping the original table, and then appending the data back into the table.

I've never had this happen before. Any ideas of what caused this?