Q100588: How to resolve the "Hiero encountered a fatal error" warning and crashes when launching Nuke on Windows



When trying to launch Nuke 12 versions on Windows, we’ve had users reporting a crash with the following error message appearing in command prompt:

Worker process failed. Hiero encountered a fatal error. This is most likely due to an unhandled exception.

The majority of reporters having this issue use a Nuke Non-Commercial, Trial, or Educational license. However, this has also been reported for commercial licenses of Nuke as well.



The Worker process failed... error message generally stems from a frame server issue, where the frame server cannot connect to the main Nuke GUI session. There are a number of things which could prevent the frame server from connecting to the GUI session, and one of the main causes seems to be having QuickTime installed.

From investigations, there appears to be several potential causes to the issue:

a) The required QuickTime directory missing from your PATH environment variable, or QuickTime installed in a non-English format, could affect Nuke from launching

b) The 'Apple Application Support' program is not installed on the machine.

Versions of Nuke 12.0+ went through developmental changes to reduce QuickTime dependencies, which is a potential cause for the issue to begin appearing. From our testing, this issue appears resolved in Nuke 13.0+ releases.



Below are some solutions which have prevented the behavior for users who’ve experienced the issue first-hand:

Uninstall QuickTime:

For users that have QuickTime installed, uninstalling QuickTime seems to have fixed the issue. As it will re-install the Apple Application Support program.

Install QuickTime:

If QuickTime was not installed previously, there are some instances where installing the recommended version of QuickTime 7.7.9 also assists in getting Nuke to launch correctly.

Verify the PATH environment variable:

Ensure that if QuickTime is installed, the PATH environment variable includes the installation path for QuickTime. The default value for the QuickTime path is: C:\Program Files (x86)\QuickTime\QTSystem\

QuickTime installed but disabled:

For users that encounter the issue but still require QuickTime to remain installed, please set the NUKE_QUICKTIME_ENABLE=0 environment variable.

Instructions about how to set environment variables can be found in the following article: Q100015: How To Set Environment Variables .



If you are still experiencing the crash when launching Nuke after trying the resolutions above, please open a Support request and let us know the exact issue encountered and the troubleshooting steps that have been taken.

For more information on how to open a Support request, please refer to this article: Q100064: How to raise a support ticket

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