Do you have any other versions of FIleMaker launched on the same computer, perhaps under a different user account?
If I have FileMaker 11 and 12 open at the same time, I can get this message if something in 12--such as a script attempts something that will turn sharing on in FileMaker 12.
Normally, I can ignore the warning as I am not actually sharing anything and don't see any issues with my database when I do so.
No, there are no other versions installed, but good thought.
You are right that I can seem to ignore the warning with no ill effect, it is just annoying.
Well, the FileMaker Cannon has never been able to share files, but simply blasts tiny pieces across the port bow of a nearby pirate ship. It hasn't even been released yet. Besides, the beta version simply blasts tiny pieces across the port bow of a nearby pirate ship.
On a serious note, uninstall and reinstall FileMaker Pro. If that doesn't fix it, try in a new user account. If that doesn't fix it, reinstall your operating system. If that doesn't fix it, you need a new computer.
If the message comes up in one database and not others, you might backup the database by Save As Smaller and another Save As Clone.
I would duplicate the two backups (smaller and clone) and run a recover (Filemaker File Menu) and see if errors are reported.http://www.filemaker.com/12help/html/recover.40.5.html
Special notes on file recoveryIn general, recovering a file should be reserved for files that will not open or are displaying index problems. Try to save a compacted copy of the file first. Databases that are returning records incorrectly from a find should be fixed by saving a compacted copy (see Saving a compacted copy).The Recover command aggressively attempts to correct a file so you can open it and recover your data. To do this, the recovery process may delete corrupted fields, layouts, layout objects, scripts, and data. For this reason, you should only use the Recover command when you cannot open a file. Do not use this command for regular file maintenance.Note There are many other conditions that return incorrect find results, including mismatched field types. Also, records might be unexpectedly deleted by a misplaced script step or an option set in the Edit Relationship dialog box. Be certain you have eliminated all other possibilities before assuming that a file is damaged and must be recovered.
How to Recover a Corrupted FileMaker Pro file