Solution for viewer taking ages to open an epub

DVdm · 02-08-2023, 03:16 PM

I think I found the cause of the extremely slow opening of epub-books with the Calibre viewer, an annoyance that has been there for ages.
Some books indeed take over 5 minutes to open, and some I have to interrupt and decide that they probably will never manage to open. I created a test book with one sentence on one page and tried opening it. It took 3 minutes to open.
On the other hand, when I open a book by going to the epub-file folder and double clicking it, it opens within seconds.

With the task manager I noticed that, when opening outside of Calibre, there's a process called "The calibre e-book viewer", whereas when I open an epub from within Calibre, I get a process called "calibre worker process".

So, I tried this:
Go to 'Preferences', 'Behaviour', 'Use internal viewer for', UNcheck (!) the entry for EPUB, which was checked on my system (Calibre portable 6.12 on WIN10 Pro).

When I do that, all my e-books open immediately with a process called "The calibre e-book viewer" and that horrible delay is no longer there.
PHEW, what an infinite relief!

kovidgoyal · 02-08-2023, 09:30 PM

The correct solution for this is to find out what software on your system (most likely the antivirus) is interfering with one type of process and not the other and stop it from doing so.

DVdm · 02-09-2023, 03:56 AM

Hmmm, yes. I have standard, up-to-date Windows Defender from WIN10.

I stopped my antivirus (real-time, cloud, and manupulation protection) , re-enabled EPUB for 'Use internal viewer for', and tried opening some books. They all opend very fast.
Ok, so then, one by one I restarted the protection processes, and each time tried opening some books again. With success!

To be sure I restarted the system and tried once more. Everything opens fast.
Perhaps some protection process was preventing some calibre cache to be cleared or something? Strange.

I'll leave the setting as it is now and will come back here if/when the problem might re-emerge...

DVdm · 02-09-2023, 07:02 PM

Back already. Books don't open at all anymore.
Stopping antivirus doesn't help.
Unchecking EPUB for internal viewer doesn't help.
Externally opening book works perfectly.
I decided to let it try for about 10 minutes. From then it works again.
I am leaving EPUB unchecked now.
Is there some kind of logfile I can consult and/or perhaps send over?

kovidgoyal · 02-09-2023, 09:28 PM

This is not anything in calibre so logfiles wont help. Its something interfering on your machine. But you can start calibre in debug mode br right clicking the preferences button.

enuddleyarbl · 02-09-2023, 11:03 PM

Do you have an AMD gpu or cpu?

DVdm · 02-10-2023, 04:40 AM

Quote:

Originally Posted by kovidgoyal

This is not anything in calibre so logfiles wont help. Its something interfering on your machine. But you can start calibre in debug mode br right clicking the preferences button.

I'll try that next when the problem presents itself again, thanks.

Quote:

Originally Posted by enuddleyarbl

Do you have an AMD gpu or cpu?

I have a DELL Latitude E5530 with an Intel(R) Core(TM) i7-3540M CPU @ 3.00GHz.

JSWolf · 02-10-2023, 06:12 AM

Reboot into safe mode and see if it Calibre's viewer is working. If so, boot normally and try again. If it's failing, disable everything one by one. But you have to reboot in between.

gentlemagic · 02-11-2023, 01:47 PM

I have slow issue too with an epub have many images, many embeded videos, and file size 265MB, loading time 20s.
Luckily after read a lot of forum posts I solve it by steps:
1. Turn off hardware virtualization in Kaspersky reduce loading time from 20s to
12s
2. In graphic card control , I change Tessellation mode to applications setting, and bang! loading times now 1s

JSWolf · 02-11-2023, 01:54 PM

Quote:

Originally Posted by gentlemagic

I have slow issue too with an epub have many images, many embeded videos, and file size 265MB, loading time 20s.
Luckily after read a lot of forum posts I solve it by steps:
1. Turn off hardware virtualization in Kaspersky reduce loading time from 20s to
12s
2. In graphic card control , I change Tessellation mode to applications setting, and bang! loading times now 1s

Kaspersky is garbage and really should be deleted from your system.

DVdm · 02-14-2023, 06:25 AM

HELP!
Opening any book withing calibre takes ages for any book in my library.
Does not depend on any setting: antivirus on/off, starting with/without plugins, using EPUB-check/unckeck in Use internal viewer.
Nothing helps anymore.
O.t.o.h, directly opening by double clicking the .epub in the book directory takes a few seconds for any book, even for the largest ones.
Even when I try to open a second window from within, it hangs.
Text-files produced by restarting in debug-mode reveal nothing.

kovidgoyal · 02-14-2023, 06:27 AM

Reboot in safe mode, they will open instantly. Then reboot in normal mode turning off your background services one by one until you discover whatever is causing the issues.

DVdm · 02-14-2023, 07:45 AM

Quote:

Originally Posted by kovidgoyal

Reboot in safe mode, they will open instantly. Then reboot in normal mode turning off your background services one by one until you discover whatever is causing the issues.

Rebooted in safe mode. Same behaviour

kovidgoyal · 02-14-2023, 09:42 AM

Then you should have a much smaller set of background programs/services to check. You can open up task manager and kill them off one by one and see what makes a difference.

DVdm · 02-15-2023, 02:48 PM

Quote:

Originally Posted by kovidgoyal

Then you should have a much smaller set of background programs/services to check. You can open up task manager and kill them off one by one and see what makes a difference.

Everything seems to be OK again now.

02-08-2023, 03:16 PM	#1
DVdm Enthusiast Posts: 28 Karma: 25920 Join Date: Oct 2020 Device: Kobo Aura H2O (mark 5)	Solution for viewer taking ages to open an epub I think I found the cause of the extremely slow opening of epub-books with the Calibre viewer, an annoyance that has been there for ages. Some books indeed take over 5 minutes to open, and some I have to interrupt and decide that they probably will never manage to open. I created a test book with one sentence on one page and tried opening it. It took 3 minutes to open. On the other hand, when I open a book by going to the epub-file folder and double clicking it, it opens within seconds. With the task manager I noticed that, when opening outside of Calibre, there's a process called "The calibre e-book viewer", whereas when I open an epub from within Calibre, I get a process called "calibre worker process". So, I tried this: Go to 'Preferences', 'Behaviour', 'Use internal viewer for', UNcheck (!) the entry for EPUB, which was checked on my system (Calibre portable 6.12 on WIN10 Pro). When I do that, all my e-books open immediately with a process called "The calibre e-book viewer" and that horrible delay is no longer there. PHEW, what an infinite relief!

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02-08-2023, 09:30 PM	#2
kovidgoyal creator of calibre Posts: 44,017 Karma: 22669822 Join Date: Oct 2006 Location: Mumbai, India Device: Various	The correct solution for this is to find out what software on your system (most likely the antivirus) is interfering with one type of process and not the other and stop it from doing so.

02-09-2023, 03:56 AM	#3
DVdm Enthusiast Posts: 28 Karma: 25920 Join Date: Oct 2020 Device: Kobo Aura H2O (mark 5)	Hmmm, yes. I have standard, up-to-date Windows Defender from WIN10. I stopped my antivirus (real-time, cloud, and manupulation protection) , re-enabled EPUB for 'Use internal viewer for', and tried opening some books. They all opend very fast. Ok, so then, one by one I restarted the protection processes, and each time tried opening some books again. With success! To be sure I restarted the system and tried once more. Everything opens fast. Perhaps some protection process was preventing some calibre cache to be cleared or something? Strange. I'll leave the setting as it is now and will come back here if/when the problem might re-emerge...

02-09-2023, 07:02 PM	#4
DVdm Enthusiast Posts: 28 Karma: 25920 Join Date: Oct 2020 Device: Kobo Aura H2O (mark 5)	Back already. Books don't open at all anymore. Stopping antivirus doesn't help. Unchecking EPUB for internal viewer doesn't help. Externally opening book works perfectly. I decided to let it try for about 10 minutes. From then it works again. I am leaving EPUB unchecked now. Is there some kind of logfile I can consult and/or perhaps send over?

02-09-2023, 09:28 PM	#5
kovidgoyal creator of calibre Posts: 44,017 Karma: 22669822 Join Date: Oct 2006 Location: Mumbai, India Device: Various	This is not anything in calibre so logfiles wont help. Its something interfering on your machine. But you can start calibre in debug mode br right clicking the preferences button.

02-09-2023, 11:03 PM	#6
enuddleyarbl Guru Posts: 734 Karma: 1077122 Join Date: Sep 2013 Device: Kobo Forma	Do you have an AMD gpu or cpu?

02-10-2023, 06:12 AM	#8
JSWolf Resident Curmudgeon Posts: 74,623 Karma: 130140792 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	Reboot into safe mode and see if it Calibre's viewer is working. If so, boot normally and try again. If it's failing, disable everything one by one. But you have to reboot in between.

02-11-2023, 01:47 PM	#9
gentlemagic Junior Member Posts: 2 Karma: 10 Join Date: Feb 2023 Device: PC Windows 10	I have slow issue too with an epub have many images, many embeded videos, and file size 265MB, loading time 20s. Luckily after read a lot of forum posts I solve it by steps: 1. Turn off hardware virtualization in Kaspersky reduce loading time from 20s to 12s 2. In graphic card control , I change Tessellation mode to applications setting, and bang! loading times now 1s

02-14-2023, 06:25 AM	#11
DVdm Enthusiast Posts: 28 Karma: 25920 Join Date: Oct 2020 Device: Kobo Aura H2O (mark 5)	HELP! Opening any book withing calibre takes ages for any book in my library. Does not depend on any setting: antivirus on/off, starting with/without plugins, using EPUB-check/unckeck in Use internal viewer. Nothing helps anymore. O.t.o.h, directly opening by double clicking the .epub in the book directory takes a few seconds for any book, even for the largest ones. Even when I try to open a second window from within, it hangs. Text-files produced by restarting in debug-mode reveal nothing.

02-14-2023, 06:27 AM	#12
kovidgoyal creator of calibre Posts: 44,017 Karma: 22669822 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Reboot in safe mode, they will open instantly. Then reboot in normal mode turning off your background services one by one until you discover whatever is causing the issues.

02-14-2023, 09:42 AM	#14
kovidgoyal creator of calibre Posts: 44,017 Karma: 22669822 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Then you should have a much smaller set of background programs/services to check. You can open up task manager and kill them off one by one and see what makes a difference.

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