Recently I am seeing this issue again. The message is wrong as you do not need to restart the machine just the application. I suspect that this is something entirely separate. This typically occurs if you have many repo open (40 in my case) and SourceTree running for a long time (over a day). The bug reference you are pointing to offer a solution but also I would suggest that you allocate NSPipe too aggressively, it take some time for the autorelease pool to do its work and you probably allocation too many too quickly.