Again the application was built in 5 so the option of using multiple windows is not used throughout the application.
But with one table to a file, you DO have multiple windows open unless you only have one file open at a time. Each file will be open in its own window though only one window may be visible at the time. Next time that this happens, pull down the Windows menu and look inside the "Show Window" sub menu to see what other windows might be open but not immediately visible.
If a user leaves the cursor in a field of window 1, then opens a different file, that opens window 2 and that file's layout could include a reference to related data in a record of the first file. That could in turn trigger this "Locked in another window" error message in the current versions of FileMaker where it would not have (as far as I can recall) in Filemaker 5.
Thank you for the quick reply! I don't believe I have a very good understanding of "new window". I tend to like screens at full size and it has been my experience that every time I script a new window it messes with the everything else. Anyway, I am waiting for them to let me know when it happens again but wanted to send you a quick thank you.
If the users are clicking buttons to move around the file, look for scripts that use Go To Related Records to pull up data in another file. You may need to add a commit records step just before the GTRR step so that the record in the current window is not left edit locked in that first window.