Mel command failing in Maya 2024

[davedub]

I've been using a python script in Maya 2023 for a year with no issues. I've updated Maya to 2024. Initially, my script ran, but now it seems to be having trouble with mel commands:

mel.eval('FBXImportShapes -v true;')

gives

Error occurred during execution of MEL script
line 1: line 1: Cannot find procedure "FBXImportShapes".

So I tried the mel command in a mel tab:

FBXImportShapes -v true;

which gave

FBXImportShapes -v false;
// Error: line 1: Cannot find procedure "FBXImportShapes"

For reference, this is what I get if I run the exact same command in Maya 2023:

FBXImportShapes -v false;
// Result: Success

Simple mel commands (e.g. polySphere) work fine. Perhaps there is a section of the mel library that deals with fbx files that has not been loaded properly?

Just as background, I have installed PyMel in Maya 2024 and had to do some strange copying and renaming trick to get it to work (see https://www.autodesk.com/support/technical/article/caas/tsarticles/ts/6gfZgdPquwZ2qCVxfAkb1n.html)

As I say, Maya 2024 worked initially, running my script with no issues. At one point, I had one instance of Maya 2024 running my script with no problems and another refusing to run the exact same script!

I'm very much hoping this can be fixed, as the users of my script are asking for Maya 2024 support...

[absoluteKelvin]

could be a he fbx plugin not loaded?

[davedub]

I contacted support and after a couple of tests they advised that I deleted my prefs folder. This fixed the issue. It was a brand new install of Maya 2024, so I have no idea how the prefs got corrupted.

[brentmc]

Actual preference corruption is extremely rare.

Rather Maya persists almost all tool and command settings in the preferences so when you fire up a fresh instance of Maya it has the same state as the last time. So, in most situations it is easier to reset all the preferences than trying to figure out which setting is to blame.

Note: In recent versions of Maya the userPrefs.mel file is organized by catefory and only saves out non-default values which does make it much easier to go in and fix individual settings or see what has been changed.

[davedub]

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@brentmc wrote:

Actual preference corruption is extremely rare.

Rather Maya persists almost all tool and command settings in the preferences so when you fire up a fresh instance of Maya it has the same state as the last time. So, in most situations it is easier to reset all the preferences than trying to figure out which setting is to blame.

Note: In recent versions of Maya the userPrefs.mel file is organized by catefory and only saves out non-default values which does make it much easier to go in and fix individual settings or see what has been changed.

---

Given that Maya persists tool and command settings in the preferences, I'm still unclear as to what inside the folder could have caused Maya to stop recognising certain mel commands. But hey, it's all working now!

[brentmc · Accepted solution]

Like the other commenter previously said, I think the fbxmaya plugin became unloaded and Maya persisted that state.

I don't think it was anything specifically you did but it can occaisionally happen and the easiest fix (assuming this is the problem) is to go into Windows > Settings/Preferences > Plug-in Manager and re-enable the plugin.

[davedub]

Ok, yes, that does make sense. If it happens again I'll check the enabled plugins.

Thank you for taking the time to answer.