I can open a .pln file in version 22 but if I try to open the teamwork file of that same .pln, it crashes on opening. Sometimes I can get it to open once, and it works fine for a bit. If I close and reopen the file, it goes back to crashing. No one else is working in the teamwork file at the moment, so no changes have been made. I have had other people in the office try opening the teamwork file. They have not had any issues. All computers are working with Mac OS High Sierra. The only difference is that my computer is older by a year or two.
I have never had a problem with Version 21. I also tried uninstalling then a complete reinstall with all updates. Still getting the same error message that there is a bug and if I want to send an error report.
Although others do not experience the crashes, it is possible that the issue is in the file, not in the system. The best would be if we could examine the mentioned pln file and a Bug report which was created after ARCHICAD crashed. I sent you a private message.