The "Data File Utilities" menu item is designed to ensure the integrity of the main data file. Over time, errors may appear in the file, which may, in turn, cause data loss. There are many ways to prevent this (see screenshot below).

The "Quickcheck" option will scan over the data file to make sure that there are no errors.

The "Checkdata" will scan all data records and make sure that each data element is not corrupt. This is a more comprehensive diagnostic than the Quickcheck.

In the first two options, checking the "Perform repairs" option will cause the program to automatically re-write the data file as it sees fit to repair any corruption encountered. Otherwise, the program will prompt the user whenever errors are encountered and ask if repairs should be done.

"Reorganize" will re-construct the data file, and should only be used whenever a new version of MIRROR is installed and is using a data file saved under a previous version.