Unable to open .mobi or .epub in windows

[eloigorri]

Hi Newbie here,
I have just installed Calibre v4.18.0 on my Windows 8 pc.
I am unable to view either .mobi or .epub files with the Calibre viewer or Editor.
I get a splash screen stating "Preparing to view ebook", which flashes up briefly and then disappears. No error message.

I can convert files .docx to mobi, epub but not view them.
The problem is also occurring with the supplied "Quick Start Guide.epub" so nothing to do with my own book conversions.

Is there a debug log which would give a better clue of what is failing?

Thanks - E

[georgemk]

To activate Calibre in debug mode, you restart Calibre using Control - Shift - R

[eloigorri]

Thanks,
This is the log that was produced after attempting to view and also edit the supplied startup .epub book.

Looking at the log, the problem appears to be due to some kind of timeout [Errno 10060]?

Any ideas as to the cause?

Cheers - E

Spoiler:

calibre Debug log
calibre 4.18 [64bit] embedded-python: True is64bit: True
Windows-8-6.2.9200-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '8', '6.2.9200')
Python 2.7.16+
Windows: ('8', '6.2.9200', 'SP0', u'Multiprocessor Free')
Interface language: None
Successfully initialized third party plugins: Count Pages (1, 9, 2)
calibre 4.18 [64bit] embedded-python: True is64bit: True
Windows-8-6.2.9200-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '8', '6.2.9200')
Python 2.7.16+
Windows: ('8', '6.2.9200', 'SP0', u'Multiprocessor Free')
Interface language: None
Successfully initialized third party plugins: Count Pages (1, 9, 2)
Turning on automatic hidpi scaling
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 140.137931034 x 142.875
Using calibre Qt style: True
[0.00] Starting up...
[0.00] Showing splash screen...
[0.39] splash screen shown
[0.39] Initializing db...
[0.39] db initialized
[0.39] Constructing main UI...
[1.69] main UI initialized...
[1.69] Hiding splash screen
[5.11] splash screen hidden
[5.11] Started up in 5.11 seconds with 2 books
Worker Launch took: 0.121000051498
Failed to check for calibre update: [Errno 10060] A connection attempt failed because the connected party did not properly respond after a

period of time, or established connection failed because connected host has failed to respond
Worker Launch took: 0.144999980927
Worker Launch took: 0.15700006485

[theducks]

the timeout appears to be just a update check.

But the same cause might be blocking the use of the Viewer or editor workers.

Your (current) security settings are the most likley.

[kovidgoyal]

When you say disappears does it mean the process crashes or does it mena just that the window is hidden? If the former try turning off hardware acceleration as described here: https://doc.qt.io/qt-5/qtwebengine-debugging.html

[eloigorri]

Originally Posted by theducks

the timeout appears to be just a update check.

But the same cause might be blocking the use of the Viewer or editor workers.

Your (current) security settings are the most likley.

I have set administrator rights to Calibre and its directory, but still no joy, and Calibre was/is working fine, so I am not sure it is security settings.
Are there any other debug tools that would help narrow down the cause of the problem?

Thanks - E

[DNSB]

I'm wondering if this is a graphics driver issue? It sounds rather similar to the issues that made Windows 7 a not recommended OS for calibre 4.0+. Perhaps a check for a replacement graphics card driver or an update to Windows 8.1 or 10 might be helpful.

[BetterRed]

Originally Posted by eloigorri

I have set administrator rights to Calibre and its directory, but still no joy, and Calibre was/is working fine, so I am not sure it is security settings.
Are there any other debug tools that would help narrow down the cause of the problem?

Thanks - E

It may not be a video driver issue.

The posts (starting at #12) between myself and the OP (Harakane) in this thread may offer a solution (as it has to couple of others with similar problems) ==>> [Help] Calibre 4.X eBook Viewer Broken.

BR

[eloigorri]

Thanks for the link to the previous thread.
My install was brand new to v4.18.0 I hadnever installed Calibre previously, so it cannot be damaged registry entries or left behind files from an older version.

Just in case.. my display adapter driver is an Intel HD Graphics 4000.

I am unable to run either the viewer or the editor directly from inside the directory either. When it executes, the screen just flashes up and disappears.

Cheers - E

[BetterRed]

There wouldn't be many using calibre 4.x on Windows 8, so maybe it's a Qt issue related to that. Most people I know skipped 8 and went straight from 7 to 10 or are still using 7.

Try uninstalling what you have and installing calibre version 3.84, old versions are here.

Or upgrade to Windows 10.

BR

[eloigorri]

I installed 3.84 after uninstalling v4.18.0 and that did the trick. Both the viewer and editor are now working.
Curiously all my previously installed Calibre plug-ins also reappeared automatically within the older version of Calibre, so I guess some registry entries must have been left behind.

Thanks for your help.

Cheers - E

[BetterRed]

Thanks, know we know that Calibre 4.x might not work on Windows 8 Ψ³

FYI: Calibre does not store its settings in the registry, they're in %appdata%; a click on the Preferences->Miscellaneous->User configuration directory button will take you there. They don't get deleted if calibre is uninstalled, ditto calibre libraries.

BR