If you have your RentMaster set up for multiple users across a network, then it is important that each computer is using the same software version.  Dont update one computer and not the others.  The reason is because when the software is updated to a new version, there are sometimes changes made to the database, which all computers are sharing.  However the software using the older version does not know about that database change, and so the data that is being saved on the older version may not be compatible with the new database setup.

In the next version I will try to find some way of limiting the operation of the software if the database is a newer version than the current software installed on the computer to stop this occurance from happening.  But for now you as users will have to be careful.  Just go to the help menu and choose About Rentmaster to find out the RentMaster version on that computer.