Viewer and Editor have stopped working in Calibre

ianmacdo · 06-09-2026, 04:15 PM

Viewer and Editor have stopped working in Calibre.
If I try to open an epub nothing happens. View or Edit book.

Im running a desktop(too old for win11) with windows 10.
I don't know what version this started with. I usually just use calibre for loading my kobo and that still works fine. It used to work fine though.

calibre-debug -w
---------------
QPA platform: windows
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 81.55183946488295 x 81.64285714285714
ApplicationPaletteChange event ignored
Using calibre Qt style: True
ApplicationPaletteChange event received
Sandboxing disabled by user.

I tried downloading the calibre portable version, still doesn't work.

I tried starting windows in safe mode, and then the viewer now works, but only in safe mode, back in regular mode it does not work.

Thanks for any help.

BetterRed · 06-09-2026, 06:55 PM

Quote:

Originally Posted by ianmacdo

Viewer and Editor have stopped working in Calibre.
If I try to open an epub nothing happens. View or Edit book.

Im running a desktop(too old for win11) with windows 10.
I don't know what version this started with. I usually just use calibre for loading my kobo and that still works fine. It used to work fine though.

calibre-debug -w
---------------
QPA platform: windows
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 81.55183946488295 x 81.64285714285714
ApplicationPaletteChange event ignored
Using calibre Qt style: True
ApplicationPaletteChange event received
Sandboxing disabled by user.

I tried downloading the calibre portable version, still doesn't work.

I tried starting windows in safe mode, and then the viewer now works, but only in safe mode, back in regular mode it does not work.

Thanks for any help.

The fact that portable does have the problem, and Safe mode doesn't leads me to conclude the problem is most likely being caused by a 3rd party application that you run at start up.

You can make use of the Windows Task Manager Startup tab to selectively disable programs to determine which one is the culprit.

BR

ianmacdo · 06-23-2026, 12:49 AM

It wasn't any 3rd party application.

I managed to solve this by a coincidence.
I tried playing the free steam game Magic Archery, and it would not load at all, like nothing happened when launched, same as the calibre viewer. But with magic archery someone suggested launching it from the cmd prompt window, and there I saw the log, opengl 3.3 not supported. Which should not show with my video card...

So I ended up removing my nvidia drivers, and reinstalling them. And now everything works fine. No idea how it got messed up in the first place.

06-09-2026, 04:15 PM	#1
ianmacdo Junior Member Posts: 6 Karma: 10 Join Date: Jun 2014 Device: Kobo Aura ONE	Viewer and Editor have stopped working in Calibre Viewer and Editor have stopped working in Calibre. If I try to open an epub nothing happens. View or Edit book. Im running a desktop(too old for win11) with windows 10. I don't know what version this started with. I usually just use calibre for loading my kobo and that still works fine. It used to work fine though. calibre-debug -w --------------- QPA platform: windows devicePixelRatio: 1.0 logicalDpi: 96.0 x 96.0 physicalDpi: 81.55183946488295 x 81.64285714285714 ApplicationPaletteChange event ignored Using calibre Qt style: True ApplicationPaletteChange event received Sandboxing disabled by user. I tried downloading the calibre portable version, still doesn't work. I tried starting windows in safe mode, and then the viewer now works, but only in safe mode, back in regular mode it does not work. Thanks for any help.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Editor stopped working (v7.13)	lMonk	Editor	6	07-20-2024 03:07 AM
ebook viewer stopped working after importing library	OregaNooo	Viewer	4	11-12-2022 03:24 PM
Viewer has stopped working.	rolgiati	Viewer	4	04-22-2022 07:13 AM
Calibre epub editor stopped working entirely!	kwnewton	Editor	3	10-17-2020 03:54 PM
@media okay in editor; not working in E-book viewer	rjwse@aol.com	Editor	4	07-12-2016 12:15 AM

06-23-2026, 12:49 AM	#3
ianmacdo Junior Member Posts: 6 Karma: 10 Join Date: Jun 2014 Device: Kobo Aura ONE	It wasn't any 3rd party application. I managed to solve this by a coincidence. I tried playing the free steam game Magic Archery, and it would not load at all, like nothing happened when launched, same as the calibre viewer. But with magic archery someone suggested launching it from the cmd prompt window, and there I saw the log, opengl 3.3 not supported. Which should not show with my video card... So I ended up removing my nvidia drivers, and reinstalling them. And now everything works fine. No idea how it got messed up in the first place.