This issue usually occurs due to a corrupted record in the table or some underlying locking mechanism in the database.
Here are the steps to resolve this problem:

1. Open the Table Directly
   - Open the table associated with the form directly in Datasheet View.
   - Locate and delete the problematic record manually.
   - If you can't find the record, sort the table by recent entries or check for blank or corrupted records.

2. Compact and Repair the Database
   - Go to Database Tools -- Compact and Repair Database.
   - This will fix minor corruption and clean up locking issues.

3. Check for Active Locks
   - If you have a split database:
     - Look for the `.laccdb` file in the same folder as your database.
     - Close the database and ensure no `.laccdb` file remains. If it does, delete it manually (ensure no one else is using the database).
   - If the database is not split, splitting it might prevent future issues:
     - Use Database Tools -- Access Database to split it into a front-end and back-end database.

4. Delete Temporary Data
   - If Access is stuck with a "phantom" record, you can force the database to reset:
     - Close Access completely.
     - Reopen Access but hold down the Shift key while opening your database to bypass start-up macros or forms.
     - Go to the table or query level and attempt to delete the problematic data.

5. Backup and Test
   - Before making significant changes, back up your database.
   - If the above steps don't work, try creating a new, empty database and importing all objects (tables, queries, forms, etc.) into it:
     - Use External Data -- Import -- Access.
     - This can resolve corruption in the original file.

6. Test the Form
   - Open the form in Design View and ensure there are no unhandled events or circular references that might be causing the error.
   - Check the form's RecordSource for any filtering or queries that could be causing conflicts.

Thank you so much for your prompt reply.  I will try this.