Calibre 7.24 not starting on Windows 11

[straygrunt]

Morning

I installed Calibre on my machine but it won't start up. The error I get is 'This application failed because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.'

Reinstalling didn't fix it, so I figured I'd ask here. Where do I locate this particular plugin?

Thanks

Shawn

[kovidgoyal]

https://manual.calibre-ebook.com/faq...ing-on-windows

[straygrunt]

Thanks for the reply.

I don't see this particular problem in the FAQ. I'd already worked through the document and I reached the point where it says run the debug and post results. I get the same error I posted above in both a pop-up within Windows and when I run the debug.

Shawn

[kovidgoyal]

That error means Qt in unable to initialize its windows platform plugin. You say you did a re-install, but maybe try a clean one. That is uninstall, delete c:\program files]calibre2 then re-install.

[straygrunt]

Thanks

I had tried that as well. Is there a way to nudge the plugin?

Shawn

[PeterT]

Any details on your PC? Is Windows fully up to date? Video Card and drivers? Are there multiple video cards?

Sent from my Pixel 7a using Tapatalk

[JSWolf]

Originally Posted by straygrunt

Thanks

I had tried that as well. Is there a way to nudge the plugin?

Shawn

Go to c:\users\<username>\appdata\roaming and rename the directory calibre to calibre.bak. Then start calibre and see if it runs. If it does, exit calibre, rename the new calibre settings directory and rename calibre.bak back to calibre. Then go into calibre and rename gui.json to gui.json.bak and see if calibre runs. if it does, the problem is in gui.json. If not, it's something else in your settings.

[straygrunt]

Morning

The renaming didn't work. It still throws the error. My machine is a Windows 11, fully patched. It has a Radeon RX 6700RT, also up to date. Is there anything else I can try? I appreciate the help.

Shawn

[kovidgoyal]

post the actual output from calibre-debug -g in the command prompt not the error popup

[straygrunt]

Below is what I get with the debug command.

calibre 7.24 embedded-python: True
Windows-10-10.0.26100-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.26100')
Python 3.11.5
Windows: ('10', '10.0.26100', 'SP0', 'Multiprocessor Free')
Interface language: None
EXE path: D:\Applications\calibre-debug.exe
qt.qpa.plugin: Could not find the Qt platform plugin "windows" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Shawn

[DiapDealer]

Originally Posted by straygrunt

EXE path: D:\Applications\calibre-debug.exe
qt.qpa.plugin: Could not find the Qt platform plugin "windows" in ""

Did you relocate calibre-debug.exe? I could be wrong, but that doesn't look the right path even for a portable install of calibre.

[straygrunt]

I haven't tried anything outside of just installing it and then renaming the folder as a test, based on instructions above. Do I need to move a file?

Shawn

[DiapDealer]

Originally Posted by straygrunt

I haven't tried anything outside of just installing it and then renaming the folder as a test, based on instructions above. Do I need to move a file?

Shawn

You misunderstood the folder they were telling you to rename. Nobody suggested renaming the installation folder (not that that should matter).

[straygrunt]

Mmm. The instructions were

'Go to c:\users\<username>\appdata\roaming and rename the directory calibre to calibre.bak.'

This I did, and when it didn't work, I changed it back. Did I miss something?

Shawn

[JSWolf]

Originally Posted by straygrunt

I haven't tried anything outside of just installing it and then renaming the folder as a test, based on instructions above. Do I need to move a file?

Shawn

Try adding this environment variable. Reboot after adding it.

QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu"