Calibre crashes at startup with AttributeError: 'NoneType' object has no attribute 'cancel'

Bug #1898904 reported by grofaty on 2020-10-07
This bug affects 43 people
Affects Status Importance Assigned to Milestone
calibre (Ubuntu)

Bug Description

On Ubuntu 20.04 few months ago I installed Calibre from Ubuntu Store official repository.

I have been using Calibre for months, but today opening it from Ubuntu Launcher and nothing happens, no error.

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

calibre --version
calibre (calibre 4.99.4)

I tried:
sudo apt purge calibre
sudo apt autoremove
sudo apt install calibre
but the problem is the same.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: calibre 4.99.4+dfsg+really4.12.0-1build1
ProcVersionSignature: Ubuntu 5.4.0-48.52-generic 5.4.60
Uname: Linux 5.4.0-48-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Wed Oct 7 18:07:57 2020
InstallationDate: Installed on 2019-10-23 (350 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
PackageArchitecture: all
SourcePackage: calibre
UpgradeStatus: Upgraded to focal on 2020-08-14 (54 days ago)
modified.conffile..etc.default.apport: [modified]
mtime.conffile..etc.default.apport: 2020-04-29T17:08:03.553351

grofaty (grofaty) wrote :
grofaty (grofaty) on 2020-10-07
summary: - Calibre does not start anymore
+ Calibre crashes at startup with "/usr/bin/calibre, line 20" error

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in calibre (Ubuntu):
status: New → Confirmed
Juanjo Benages (juanjo-benages) wrote :

I forgot to upload the patch.

The attachment "7b6416ac6522fc40f24f6baf3ca552b17a8b91d6.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

tags: added: patch
Evan Huus (eapache) wrote :

Per this happens on python >= 3.8.3. As Focal ships 3.8.5 we get this bug. Juanjo linked and attached the upstream patch already, which is included in Calibre >= 4.15. Focal ships Calibre version 4.99.4 which I assume is some pre-release version of the Calibre 5 series which didn't yet include this fix. Calibre 5 is now available and presumably would also fix this issue.

summary: - Calibre crashes at startup with "/usr/bin/calibre, line 20" error
+ Calibre crashes at startup with AttributeError: 'NoneType' object has no
+ attribute 'cancel'
Evan Huus (eapache) wrote :

As a work-around for those affected, I can confirm that manually applying the upstream patch to `/usr/lib/calibre/calibre/utils/ipc/` does allow Calibre to start up successfully.

grofaty (grofaty) wrote :

Evans, great thanks for info how to fix, it works fine.

I have written bash file for the users that are not so technical.

1. Download file from my post.
2. Open terminal, default keyboard shortcut is: CTRL+ALT+T
3. Set execution permissions: chown 700
4. Execute commands: ./
5. Then you can delete file: rm

Hope this helps for others too.

P.S. For non-technical users, package maintainer that has packaged original Calibre program in Ubuntu 20.04, please update the package and push it to official Ubuntu repository.

grofaty (grofaty) wrote :

Ahhh, sorry bug in instructions above in step 3 should be:
chmod 700

I have uploaded a patched version of calibre to a ppa:

It works for me. It should work as an interim until there is an updated package in the official Ubuntu repository.

Timo Aaltonen (tjaalton) on 2020-10-14
Changed in calibre (Ubuntu):
status: Confirmed → Fix Released
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in calibre (Ubuntu Focal):
status: New → Confirmed
Norbert (nrbrtx) wrote :

Patch applied. Thanks!

Hope the package in the repository will be fixed soon.

Bill (franksmcb) (franksmcb) wrote :

Applied patch and can confirm it resolves the issue.

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