Are you running Windows 7 by any chance?
There was a bad update from Microsoft last week.
http://archicad-talk.graphisoft.com/viewtopic.php?t=50877
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.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11