Need advice on tracking App hang after many days of runtime :-)

Steps causing the bug to occur

I use a Vuo app as part of an installation and it hangs after a week or two requiring a full system restart. There doesn’t seem to be any specific cause, so I’m guessing it’s a memory-leak type of issue in Vuo or some related system component. But I’m not sure what I can do to help find the problem.

Have you found a workaround?


Other notes

  • Vuo version: 2.2.1
  • macOS version: macOS 10.15
  • How severely does this bug affect you? It prevents me from completing a specific task with Vuo.

The app is a Motion Monitor that reports motion across a video frame.


Is this a Vuo composition or an exported app? Can you please send us any hang reports or crash reports? You might see crash reports under User Reports and hang reports under System Reports. If not, when it happens again, please follow the instructions on and send us your output. Thanks for letting us know!

Hi Jean Marie, it’s running as an exported app. I’ve learned a little more: the only symptom that something is wrong is the app stops working, and refuses to Quit. I didn’t see anything noteworthy on the console until I Forced Quit when there were numerous mDNSResponder messages. I’m attaching those messages in case it’s useful. The app has no network features (other than using OSC locally) but it does seem as though the problem has started since we enabled WiFi to support entirely unrelated network functionality. Does this info help at all?  

console log.rtf (209 KB)

When you Forced Quit, is there a hang report created in your Console app under System Reports? That would be very helpful.  

I looked but didn’t see anything. Are they always generated? If so, I’m happy go back to the gallery and search again.


I know this can be so frustrating! My colleagues say sometimes a hang report isn’t generated. If a hang report wasn’t automatically generated, then the next time the app hangs, please take a process sample (see and, if macOS gives the option to see a report after force quitting, open, save it, and send it to us.

Hi Jean Marie, I’m attaching two process sample files, one taken when the App was no longer working (but Task Manager didn’t show it as unresponsive) and a second after I tried to Quit (and it has failed to do so). I’m also including the Vuo source and executable in case they are useful.

As 2.3.0 was just released I re-Exported the App and am now running that at the gallery. If we are lucky the problem will have gone away!

MoMo 10x1 6.010.vuo (32.6 KB)

MoMo 10x1 (1.25 MB)

Sample of MoMo 10x1 6.0.10 Before Quit Requested.txt (98.8 KB)

Sample of MoMo 10x1 6.0.10 After Quit Requested.txt (98.1 KB)

Thanks for the additional files. We’ve accepted the bug report. Let us know if you encounter the same issue in Vuo 2.3.0.

Unfortunately I do have a new data point: Exporting in 2.3.0 has not fixed the problem. One minor addition: I noticed that after I try and Quit the unresponsive app the Force Quit dialog box never shows it as ‘Not Responding’ in Red - as usually happens with other failed Apps. But a Force Quit is needed to terminate it. (If I then start a new instance it works fine, as does the VDMX project which uses it.)
Other System info: MacBook Pro 15" (2015) with macOS 10.5 and the latest updates. Ableton Live 10 is also running on the system. Thanks!