We haven’t been able to reproduce it here yet. Can you send the file into tech@mcneel.com and reference this forum thread in the comments? Let us know if the file is confidential as well please. If you see a pattern in what you’re doing or how long your Rhino session is when this occurs please let me know those details as well. As soon as we can reproduce it on a developer’s Mac (@dan ), we’ll be closer to figuring out what’s happening. Thanks!