You have a cascading delete set up in a relationship in Manage | Database | relationships.
Double click the line between a table occurrence (could be more than one that you need to check) of the table from which she deleted a record and a table occurrence of the table from which the extra records disappeared (could be the same table).
Clear the check box titled: "Delete Related Records in this table when a record is deleted in the other table".
It's filemaker's delete button at the top of the window, not a button on the layout.
Ok, that was what happened. i knew *I* hadn't created any realtionship like that. but apparently while i was out of town one of my coworkers thought they could fix something and went mucking around in the relationships. Thank you for reminding me to check that!!
one of my coworkers thought they could fix something and went mucking around in the relationships
You might want to put a password on the file so that other users can't modify design details. If you set it up right, the users need not know the password is there. It can open automatically with the limited access password. Then, when you need to pop the hood and make changes, you open the DB while holding down shift (windows) or option (mac) and it will ask you for a password so that you can enter the appropriate full access password that permits design changes.
I do have most users locked out of doing much more than reading and creating records, but I'm only here for a few more weeks and have been desperately trying to train my replacement (the one who went mucking around). once I'm not here she needs to be able to continue learning and updating if she can, so she at least needs access.