From Dwayne Wright PMP, PMI-ACP, CSM
Certified FileMaker Developer
There is a condition that will look like a security operation but it is not. It is a normal database action to insure data integrity of the database records.
When a FileMaker database is being hosted over a network, only one user can modify the same record at one time. If you try to modify a record that another FileMaker user is currently browsing or editing, you will get a message telling you that modifications cannot be done. The dialog box will also provide the name of the user that is on that record. This is how databases protect themselves from editing conflicts. Another term for record locking is concurrency.
By the way, another user can mean you, my friend. Yes, it is possible to lock yourself out of a record. FileMaker has be ability to have multiple windows open and it is quite possible both windows are on the same record. So it is possible for you to lock the record in one window and thereby be refused to modify that record in the other window. So it is possible to experience record locking in single user mode.