Just to inform you: PC Navigator 12.3.0 / Menu / Settings / About:
When the list of downloaded maps exceeds the window size, you have to click into the windows with the maps, then you are able to scroll down to see the rest of the information. When I then scroll back to the top of the listing the program crashes with a windows system error (Windows 8.1 64-bit),
I have the same Windows, and everything is /and was/ o.k., so try install it /or run/ as admin, or change compability /run program in compability mode/, check Your hardware /run diagnostic program, clear Your Windows registry/ or download program again. You can also check Device Manager, and manually check for updates.
This error happens since I installed 12.3.0 (from scratch), everything else in this program works alright. The former version 12.1.0 had no errors, so I don't think it has something to do with my PC.