Installed Calibre won't open, downloaded won't install

RBW · 04-07-2023, 09:24 PM

Absolute beginner on Forum, but long time user of Calibre.

1. Installed version which worked last week in Windows 11 environment gives error message "This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem."

2. Downloaded new version 6.15 (tried three times, same result), when double clicked to install gives error message "This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package"

3. Read old threads on this issue with older versions of Windows. Checked permissions and believe I have Full Control (properties, security).

4. Have Webroot security - don't see issue there (but may not be looking in right place).

Please help.

BetterRed · 04-07-2023, 09:39 PM

Try this:

Using System File Checker in Windows - Microsoft Support

Moderator Notice
Please don't post replies to 10 year old threads unless you're very, very sure you have the same problem

Read the stickies at the top of the subforums - e.g. PLEASE READ BEFORE POSTING HERE - Purpose of Development subforum.

And don't create multiple threads on the same issue.

BR

kovidgoyal · 04-07-2023, 10:31 PM

https://manual.calibre-ebook.com/faq...is-not-working

RBW · 04-07-2023, 10:41 PM

Ran SFC tools, problem remains.

Had already read Sticky - couldn't find any place else to ask question. And still seems to be correct place, although none of the posted threads on this topic include a viable solution.

kovidgoyal · 04-07-2023, 10:46 PM

reboot in safe mode then run the installer.

RBW · 04-07-2023, 11:13 PM

Quote:

Originally Posted by kovidgoyal

https://manual.calibre-ebook.com/faq...is-not-working

I was able to use Calibre portable to get Calibre to run. I can't follow the instructions to Export data from the old version because when I attempt anything on the old version, I get the error message about lacking QT plugin platform. Any thoughts on how to get existing library into new version?

ALso I'm beginning to think that some of the problem is related to OneDrive taking ownership of files on my laptop and possibly denying Calibre access to Qt. Any thoughts?

04-07-2023, 09:24 PM	#1
RBW Junior Member Posts: 3 Karma: 10 Join Date: Apr 2023 Device: Samsung laptop but changes often	Installed Calibre won't open, downloaded won't install Absolute beginner on Forum, but long time user of Calibre. 1. Installed version which worked last week in Windows 11 environment gives error message "This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem." 2. Downloaded new version 6.15 (tried three times, same result), when double clicked to install gives error message "This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package" 3. Read old threads on this issue with older versions of Windows. Checked permissions and believe I have Full Control (properties, security). 4. Have Webroot security - don't see issue there (but may not be looking in right place). Please help.

04-07-2023, 09:39 PM	#2
BetterRed null operator (he/him) Posts: 20,583 Karma: 26954694 Join Date: Mar 2012 Location: Sydney Australia Device: none	Try this: Using System File Checker in Windows - Microsoft Support Moderator Notice Please don't post replies to 10 year old threads unless you're very, very sure you have the same problem Read the stickies at the top of the subforums - e.g. PLEASE READ BEFORE POSTING HERE - Purpose of Development subforum. And don't create multiple threads on the same issue. BR Last edited by BetterRed; 04-07-2023 at 09:42 PM.

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04-07-2023, 10:31 PM	#3
kovidgoyal creator of calibre Posts: 43,864 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	https://manual.calibre-ebook.com/faq...is-not-working

04-07-2023, 10:41 PM	#4
RBW Junior Member Posts: 3 Karma: 10 Join Date: Apr 2023 Device: Samsung laptop but changes often	Ran SFC tools, problem remains. Had already read Sticky - couldn't find any place else to ask question. And still seems to be correct place, although none of the posted threads on this topic include a viable solution.

04-07-2023, 10:46 PM	#5
kovidgoyal creator of calibre Posts: 43,864 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	reboot in safe mode then run the installer.