Calibre No Longer Working

Unfortunately, at this moment the version of Calibre that is in the 20.04 repos is version 4.99 which does not work with Python 3. To make 4.99 work you would have to patch a file yourself as shown in the bug https://bugs.launchpad.net/ubuntu/+source/calibre/+bug/1898904 or you could download it from a different repository. Either way, Canonical has not patched 4.99 to work with 20.04 yet in the official repositories.

Also, quoted from Calibre themselves:

Please do not use your distribution provided calibre package, as those are often buggy/outdated. Instead use the Binary install described below.

You can download it from https://calibre-ebook.com/download_linux

You can also run the command from that site to install it (which is actually easier to install with):

sudo -v && wget -nv -O- https://download.calibre-ebook.com/linux-installer.sh | sudo sh /dev/stdin

I have added the above command to a script called install_calibre so that I can run it anytime to update my calibre version to the newest at any time.

Hope this helps!

To fix this, it is not necessary to abandon Calibre 4.99. The cause of the crash is documented in bug #1898904, which can be fixed with a one-line patch. To manually apply the patch:

• open Terminal
• type: sudo gedit /usr/lib/calibre/calibre/utils/ipc/server.py
• in Gedit, go to line 110
• change the line:

              self._listener._unlink.cancel()
  

• to:

              if self._listener._unlink is not None:
                  self._listener._unlink.cancel()
  

• save and close Gedit

This change will be overwritten when Calibre is updated, but of course it won't matter because this bug has been fixed in the next version of Calibre.

Sorry for interupting, This may not be an ideal go around, but maybe a temporary solution. I also face the same problem, in my Ubuntu 20.04, and I decided to install the flathub version instead and its being running fine up till now.

https://flathub.org/apps/details/com.calibre_ebook.calibre