I've got a client with an ancient FileMaker system that has been running in FM11 for the past couple years.
Two of the files are starting to show some serious issues. The two files are linked together. Searching is now failing.
File A has a layout with a field from File B on it. Simple 1 to many relationship. The field from B is often used for searches. It has a value list applied to it. Searches work for 1 value only. If any other value is used the search fails. There is valid data in the file.
Figured it was a messed up index. Took the files offline, disabled the indexes for the fields and then re-enabled them. No improvement. Ran the files through Recovery and still no improvement. Recovery told me that modifications were made to the files during recovery.
The usual process would be to go back to a clean copy of the file - but they are so old, been modified so many times and we don't know how far the corruption goes back. There is no clean copy to return to. By the time the client told me there were problems any hope of using a previous backup was gone.