A previously registered copy of Atrex unexpectedly starts up as an unregistered copy.
The most common reason for this is that the central directory for the Atrex software has been changed to an incorrect folder. If you are running a single user installation, use the "Options - Locations - Reports/Central Location" function to make sure that Atrex is pointing to the correct Central folder. For version 11, it will be the "Central" folder just below the Atrex installation folder. For version 12 it will be either the "Central" folder just below the Atrex installation folder if you have upgraded from a previous version, or the \Shared\Central folder.
If you can't find the central directory, select 'Options - System Information' from the main menu, and the central directory location will be displayed in the resulting window.