An unheralded new feature of Archicad 20 was a repair to the Mac version where Archicad will continually hunt on the network for missing servers. This happens when 1) the project uses resources (libraries, external drawings, hotlinked modules) on server volumes, and 2) you open the project away from the network where the servers reside. The effect is 1) a delay when opening the project as the external resources are sought, and 2) periodic warning dialogs saying that a server with a certain IP address cannot be found.
This has been a problem since at least Archicad 9, or maybe forever and that's when I started carrying projects around. I was always told it was hard to reproduce or impossible to fix, and it doesn't happen on Windows. (I mean, they never told me the Windows thing, that's just a fact.)
In Archicad 20 it was definitely fixed for a while, and there was great celebration all around, uh, my kitchen table which is supposedly one of the few places the problem occurs. Then it returned, likely an unintended consequence of an update. I am led to believe that now the issue is impossible to reproduce, so I'm not holding by breath on a fix. I think that was the shot.
So we still need DisableCrossPlatformMountingFeatures. If you are a Mac user and this situation affects you, close Archicad, open Terminal, and paste this in:
defaults write com.graphisoft.AC-64\ 20.0.0\ USA\ v1 InputOutput -dict "DisableCrossPlatformMountingFeatures" "<true/>"
This will work for any version of Archicad back to 15, just replace the '20' with the relevant version number. (Before that, drop the '-64', and for heaven's sake please upgrade.)
Let's just say I have a feeling the next version might be in the same boat, so for your clipboard convenience:
defaults write com.graphisoft.AC-64\ 21.0.0\ USA\ v1 InputOutput -dict "DisableCrossPlatformMountingFeatures" "<true/>"