Calibre stopped working recently. Tried uninstalling and reinstalling.

When I open a terminal and call $calibre I get the following error message:

Traceback (most recent call last):
  File "/usr/bin/calibre", line 20, in <module>
  File "/usr/lib/calibre/calibre/gui_launch.py", line 73, in calibre
  File "/usr/lib/calibre/calibre/gui2/main.py", line 543, in main
    listener = create_listener()
  File "/usr/lib/calibre/calibre/gui2/main.py", line 514, in create_listener
    return Listener(address=gui_socket_address())
  File "/usr/lib/calibre/calibre/utils/ipc/server.py", line 110, in __init__
AttributeError: 'NoneType' object has no attribute 'cancel'

Do I need to install some dependency that the sudo apt install didn't get? I tried installing via command line and the software installer/updater GUI.

I'm on version Ubuntu 20.04.1 LTS. I made sure that my software in general is up to date also.

  • 3
    From what I can see, Calibre 4.99 and under (which is what is in the 20.04 repos) was written for Python 2 and not Python 3. Calibre released version 5 for Python 3 which I wish was in the repos, but you can install it from calibre-ebook.com/download_linux 20.04 no longer has Python 2. – Terrance Oct 20 at 18:53
  • @Terrance that did it thanks. Please make it an answer so I can mark it accordingly – rory Oct 20 at 18:59
  • installing the newer version (now it was 5.5) from the suggested link has worked like a charm – Quaesitor Veritatem Nov 20 at 19:47

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. Since Python 2 is EOL it is no longer installed by default into Ubuntu 20.04.

Calibre has released version 5.3.0 that works with Python 3. You can download it from https://calibre-ebook.com/download_linux

Or you can run the command from that site to install it

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

Hope this helps!

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Go to this site and download previous version. extract the file run the Calibre file (which as no extension) just double click.

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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.


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