This application failed to start because no Qt platform plugin could be initialized.

[30461515]

When starting Houdini it shows an error:This application failed to start because no Qt platform plugin could be initialized. 

Operating environment window11 (22621.1265)
Houdini19.5.435

Hlep!!

[lee_griggs]

Are you using the correct Python/non-Python version of the plugin for Houdini?

[30461515]

I installed htoa-6.1.4.1_rc2f7eb9_houdini-19.5.435_windows.exe . I think it should be right

[Stephen.Blair]

This is because the Autodesk Licensing Agent is loading the wrong Qt plugins (so the Houdini environment is overriding where the Agent looks for the Qt plugins)

https://arnoldsupport.com/2022/09/20/the-case-of-the-hrender-that-failed-to-start-adsklicensingagent...

[30461515]

When I uninstall AdskLicensing, the error will not pop up. When I start the Arnold License Manager in Houdini, after reinstalling, the error will pop up here. It does seem to be related to AdskLicensing.

How should I set QT_QPA_PLATFORM_PLUGIN_PATH=C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\AdskLicensingAgent\platforms

add "QT_QPA_PLATFORM_PLUGIN_PATH=C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\AdskLicensingAgent\platforms" in the Houdini.env?

When I do this I get another error: ：

This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.Available platform plugins are: windows (from C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\AdskLicensingAgent\platforms), minimal, offscreen, webgl, windows.

I am a novice, can you explain in detail how to operate, thank you very much

Also add: C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\AdskLicensingAgent\platforms in my computer
There is only one file in this path: qwindows.dll

[30461515]

I think I already know where the problem is.
I installed V-Ray. It caused errors in arnold.
I looked at vray_for_houdini.json in the packages directory. There are these lines of text specifying the path of the QT plug-in
{ "QT_PLUGIN_PATH" : "${HFS}/bin/Qt_plugins" },
{ "QT_QPA_PLATFORM_PLUGIN_PATH" : "${HFS}/bin/Qt_plugins/platforms" },
I think there should be a problem here.
Anyway I uninstalled V-Ray and everything is fine.

[Stephen.Blair]

OS error: Could not find module 'ai.dll' (or one of its dependencies). Try using the full path with constructor syntax.

Usually because PATH does not include the location of ai.dll (the HtoA scripts/bin folder)

This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

This is because the Autodesk Licensing Agent is loading the wrong Qt plugins (so the Houdini environment is overriding where the Agent looks for the Qt plugins)
https://arnoldsupport.com/2022/09/20/the-case-of-the-hrender-that-failed-to-start-adsklicensingagent...

[al_kidd]

I'm so glad I came across your post! V-ray was messing up Arnold for me also. I un-installed V-ray and Arnold is working fine now. 

Thank you 🙂 @30461515 @Stephen.Blair 

[manuel_hm]

@al_kidd  I created a thread in the chaos group forum (https://forums.chaos.com/forum/v-ray-for-houdini-forums/v-ray-for-houdini-solaris-usd/1190477-vray-a...)

I've been busy with Arnold lately and haven't get time to test both again for the time being, not sure which renderer "messes" which honestly, but anyhow by the end of that thread it does seem to be a way to make them work together by pointing to a specific python version path (on vray's end) in case you still need to use both, hope that helps.

[nelsonBG6C6]

Where do I change that???