Q100192: Nuke stalls and maxes out all CPU threads at 100%



Due to a known bug, Nuke may stall and max out all CPU threads at 100% on some machines. If you are encountering similar problems please follow the steps below to workaround the issue until a fix becomes available in a future Nuke version.


While this issue is still under investigation, preliminary results indicate that the problem is related to the way Nuke does its internal caching and the timings in which the Nuke processes access the CPU threads.

This is logged as a bug and you can follow its progress and subscribe to notifications via the URL below:

TP 235708 - Nuke caching occasionally blocks on some machines

The main operating system this bug has been reproduced on is Windows. If you are encountering the same problem on another OS, please contact the Support team using the "Create a Ticket" button above.


As the cause of this bug is related to thread timing, changing Nuke parameters that may affect it may provide a way of working around the issue in the interim.

This includes:

  • Limiting the threads Nuke can use via the -m flag: This can be done by launching Nuke via command line (in a Terminal/Command Prompt) with the following command:

            "C:\Program Files\Nuke13.1v2\Nuke13.1.exe" -m 3

        Additional information about thread limiting can be found here: Q100117: Launching Nuke with limited number of threads (-m flag)

        Depending on the system, the maximum number of threads that you can use until the issue occurs may vary. You will need to test different -m values until you identify the exact limit.


  • Setting the Nuke process priority in Windows Task Manager: Set this to Realtime by finding the main Nuke process in the Details tab (normally the Nuke process using the most memory), per the screenshot below:



  • Changing the Nuke process affinity in Windows Task Manager: Change this to not use all the CPUs. 
  • Uninstalling Quicktime: Uninstall Quicktime and installing an older version, for example if you use currently 7.7.9 you can uninstall that and install 7.7.6 instead. You can download Quicktime 7.7.6 here


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