The only way I know how to do this is to disconnect your network license from that machine while you start Archicad.
The easiest way to do this other than stopping the Codemeter software is to disconnect the network cable (and turn of wifi if you use that).
Once Archicad has started in demo mode then re-connect the cable.
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