Play in editor locks up after ~1 minute, killing CrashReportClient frees it again

Running on a mac, after a minute or so of playing in the editor it will lock up – the mouse moves, and I can run other applications, but there is no response to mouse clicks or selecting Quit from the menu (I’m using the more common tag “freeze” even though I’d call this a lock-up since the cursor moves and I can run other things).

If I exit the launcher and kill CrashReportClient (it won’t quit, I have to force quit, which I assume means kill -9), the editor is no longer locked up, and it now gets and processes the saved-up mouse clicks (and the first keypress) that I attempted to make when it originally locked up. After CrashReportClient is killed and isn’t respawned (because the launcher isn’t running), it no longer locks up.

This is 4.12.3 – I didn’t see this with earlier 4.12 versions, but I can’t say for sure that it wasn’t a problem earlier in 4.12. I never had this happen with 4.11 or earlier.

I have another project that is a modified (and simplified) version of this project, but that one doesn’t seem to lock up. They are both modified 3rd person projects.

Hi Westley,

If you are experiencing freezes in one version of your project and not in a simplified version of the same project, this would suggest that there is a conflict with one of your assets and not a bug in the engine itself, per se. Therefore I suggest running these troubleshooting steps to isolate the cause of the issue:

  1. Run Build>Map Check for each map (fix each item that has a number beside it, if applicable. For instance, Source Control may not apply to you)
  2. Right Click on “Content” folder in Content Browser and select “Fix Up Redirectors in Folder.”
  3. Delete your Config, Intermediate, and Saved folders (You will have to redo your Project Settings)
  4. Package your project for Mac and show Window>DeveloperTools>OutputLog; cut and paste into doc and search doc for keyword “Error” -correct these errors (or post log if you need help).

If, after you have followed these trouble shooting steps you are still experiencing “freezing” in the engine, send me a link to your project in a private message on our and, if I can reproduce the freeze here, I will enter a bug report.


Hi Westley,

Since we have not heard back from you in a few days, we are marking this thread “resolved” for tracking purposes. However, if you are still experiencing the editor locking up in UE4.12.3, please respond with the results from the troubleshooting steps posted above we will continue to investigate.



Oops, sorry, didn’t see the first reply – looks like I had some calls to a function that no longer exists, in pawns that currently aren’t used. I don’t know if that’s the cause, but I’ll fix that and see if lock-ups happen after that.


If that doesn’t correct the issue, respond and let us know and we will reopen the issue.