Corrupted Calibre library

theoldman · 02-10-2025, 01:41 PM

Hello
I have just purchased a new Kobo Clara BW. In the process of loading my EPUB library I seen to have corrupted most of my 900 files. (They load just fine on my iPad). When I attempt to load them into Calibre they do not all load. I originally had taken them from a thumb drive to load them into Calibre.

Is there a fix for this situation or do I have to start fresh and download new files! Your help would be appreciated.

DNSB · 02-10-2025, 06:13 PM

If you downloaded them on a Mac, they may have been changed from the single zip file container used by ePub to a directory with the unpacked contents of the ePub file.

There are utilities to repack them. One acquaintance recently used a utility called ePub Zip-Unzip 64 to repack a bunch of unpacked epubs. There are several other tools that will do the same task.

theoldman · 02-10-2025, 08:55 PM

Hi David. I appreciate your reply and I apologize for not understanding it. I am not as tech savvy as I would like to be.
These are individual files that I have already edited and used on both an iPad and some on my Kobo. I had them on a thumb drive and they were loaded into Calibre from that drive. When I opened Calibre a second time most of them would not load.
I am confused about your reply and I am not certain of what to do with the information that you have shared. And yes, I do have a Mac.

theoldman · 02-10-2025, 09:03 PM

Hi David. I appreciate your response and I apologize as I don’t really understand it. I am not as tech savvy as I would like to be. I loaded individual EPUB files that I previously edited on Calibre. They still work fine on an iPad. I loaded Calibre from a thumb drive and it looked fine. But when I opened Calibre a second time later most files would not open. I then uninstalled Calibre and then reinstalled it but assigned the library to my documents folder. Still no changes. I apologize as I really don’t understand your response.

Grins · 02-11-2025, 12:31 AM

Not sure what you were doing. I would have copied the files from the usb-stick to a document folder on my Mac. When looking (not opening) them using finder they should be shown as ".epub". Then I would have installed calibre on my Mac. And then I would have opened calibre, created a new library in ANOTHER folder on my Mac and added / imported the files from the first folder into calibre using the "Add books" functionality. Now you should have a "valid" library on your Mac. The original files in the first folder mentioned above could now be deleted.
And now - at last - you should be able to modify etc. the books in your library and transfer them to your Kobo.
Is that the way you have done it?

JSWolf · 02-11-2025, 04:00 PM

Quote:

Originally Posted by DNSB

If you downloaded them on a Mac, they may have been changed from the single zip file container used by ePub to a directory with the unpacked contents of the ePub file.

There are utilities to repack them. One acquaintance recently used a utility called ePub Zip-Unzip 64 to repack a bunch of unpacked epubs. There are several other tools that will do the same task.

I just had a google search on how to stop the auto-unzipping on MacOS. All I'm finding is directions to stop Safari from doing it. Would that be all that's needed or is there something else to be done?

DNSB · 02-11-2025, 11:25 PM

Quote:

Originally Posted by JSWolf

I just had a google search on how to stop the auto-unzipping on MacOS. All I'm finding is directions to stop Safari from doing it. Would that be all that's needed of is there something else to be done?

For .zip files downloaded by Safari. If you are using another program and it automatically unzips, you will have to work through that on your own.

02-10-2025, 01:41 PM	#1
theoldman Junior Member Posts: 3 Karma: 10 Join Date: Feb 2025 Device: Kobo Clara BW	Corrupted Calibre library Hello I have just purchased a new Kobo Clara BW. In the process of loading my EPUB library I seen to have corrupted most of my 900 files. (They load just fine on my iPad). When I attempt to load them into Calibre they do not all load. I originally had taken them from a thumb drive to load them into Calibre. Is there a fix for this situation or do I have to start fresh and download new files! Your help would be appreciated.

02-11-2025, 12:31 AM	#5
Grins Connoisseur Posts: 58 Karma: 216 Join Date: May 2009 Location: Germany Device: Kobo(s), Pocketbook(s), MacBook Pro, iPhone	Not sure what you were doing. I would have copied the files from the usb-stick to a document folder on my Mac. When looking (not opening) them using finder they should be shown as ".epub". Then I would have installed calibre on my Mac. And then I would have opened calibre, created a new library in ANOTHER folder on my Mac and added / imported the files from the first folder into calibre using the "Add books" functionality. Now you should have a "valid" library on your Mac. The original files in the first folder mentioned above could now be deleted. And now - at last - you should be able to modify etc. the books in your library and transfer them to your Kobo. Is that the way you have done it? Last edited by Grins; 02-11-2025 at 09:26 AM.

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02-10-2025, 06:13 PM	#2
DNSB Bibliophagist Posts: 43,418 Karma: 165170834 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	If you downloaded them on a Mac, they may have been changed from the single zip file container used by ePub to a directory with the unpacked contents of the ePub file. There are utilities to repack them. One acquaintance recently used a utility called ePub Zip-Unzip 64 to repack a bunch of unpacked epubs. There are several other tools that will do the same task.

02-10-2025, 08:55 PM	#3
theoldman Junior Member Posts: 3 Karma: 10 Join Date: Feb 2025 Device: Kobo Clara BW	Hi David. I appreciate your reply and I apologize for not understanding it. I am not as tech savvy as I would like to be. These are individual files that I have already edited and used on both an iPad and some on my Kobo. I had them on a thumb drive and they were loaded into Calibre from that drive. When I opened Calibre a second time most of them would not load. I am confused about your reply and I am not certain of what to do with the information that you have shared. And yes, I do have a Mac.

02-10-2025, 09:03 PM	#4
theoldman Junior Member Posts: 3 Karma: 10 Join Date: Feb 2025 Device: Kobo Clara BW	Hi David. I appreciate your response and I apologize as I don’t really understand it. I am not as tech savvy as I would like to be. I loaded individual EPUB files that I previously edited on Calibre. They still work fine on an iPad. I loaded Calibre from a thumb drive and it looked fine. But when I opened Calibre a second time later most files would not open. I then uninstalled Calibre and then reinstalled it but assigned the library to my documents folder. Still no changes. I apologize as I really don’t understand your response.