I tried to use the SQL 'UPDATE' statement to change a series of records, but not all records are updated. What's happening ?

The SQL engine is behaving like another user using your file with the same credentials you have. It's as if it is accessing your data from another window. This means you have to be careful when modifying records (using the ‘UPDATE’ statement). You could be in the process of modifying yourself manually, or within a script.

Because FileMaker currently does not return a record locking error when that happens, use the 'UPDATE' statement with caution.