An issues arises when attempting to change data in a file using the mfdatatools2 editor. 
This issue only occurs if a Filter is applied to isolate the record to be changed. 

To change a record the file is opened in Exclusive mode. 
Once the filter has been applied the user then selects 'Edit Record' the changes to the data record can then be made in the normal way

The user then selects 'Save Record' and is prompted to 'Confirm Changes - Yes or No'.

When 'Yes' is selected, the progress bar at the bottom of the editor indicates the record is being written, but the 'Confirm Changes' box remains in focus, and the user is again requested to selected Yes or No to confirm saving changes to the current record.

The changes at this point are not being written to the file.

Full article: https://portal.microfocus.com/s/article/KM000017309