UPDATE: Better info here.
Suddenly, Richard's AC could not open a file on the network, and would hang (rainbow ball of death) when attempting to browse a network resource, such as the Hotel. We noticed it when attempting to open another project in Attribute Manager; since the previous state of that Open dialog was viewing the Onion, hang.
All conventional treatments exhausted, I had to call tech support. They directed me to this knowledge base article, which has to with switching off a cross-platform browsing preference that we don't need anyway.
If you ever see this behavior in AC, here's the fix.
Make sure AC is not running. Open Terminal (Applications : Utilities : Terminal). Paste this text into the window and strike enter:
defaults write com.graphisoft.AC\ 9.0.0\ USA\ v1 InputOutput -dict "DisableCrossPlatformMountingFeatures" "<true/>"
That's it. Quit Terminal and relaunch AC.
Comments
We are having the same problem and have tried the same fix albeit edited to use the English International version but with no luck.
I have converted the plist file to ascii text to check that the new entry is there but it isn't instead what I have found is that it created a new file with the same name but with the file extension .plist repeated and the text entry that should have been added to the actual plist file
So I'm guessing that since I am not really up to speed with Terminal/Unix commands there is something wrong with what I have typed.
Here's the command I used
defaults write /Users/graeme/Library/Preferences/com.graphisoft.AC\ 9.0.0\ INT\ v1.plist InputOutput -dict "DisableCrossPlatformMountingFeatures" "[true/]"
Having got the command to create a new preference file I tried moving the old one out of the Preferences folder and renaming the one to have the same name as the original ie I loped off the extra .plist and it worked.
I also found you can copy these new preference files onto other peoples machines and it still works. I have posted the files here to save other folks the hassle but note they will only work with ArchiCAD International English
Download em' here
Thanks for the tip, Graeme.