Are you running Windows 7 by any chance?
There was a bad update from Microsoft last week.
It helps to add your operating system and Archicad details to you post.
Adding them to your signature in the PROFILES link at the top of the page saves you from adding them to each post manually.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10