Make an extra copy of your backups onto other
media in case you want to restore one that pre-dates the problem.
You can switch back to your file by clicking File, and selecting
your regular file from the list at the bottom.
You can try a File->RepairMoneyFile->QuickFileRepair. That is
simple, but it may not solve this. Then try I would try
making a repaired version of your file with
File->RepairMoneyFile->StandardFileRepair level 2