Qutebrowser is no longer able to load a session with more than a couple hundred tabs after an update from version 3.6.3 to 3.7.0

[u/RadoslavL]

\*\*Version info\*\*:

qutebrowser v3.7.0

Git commit: 

Backend: QtWebEngine 6.11.1

  based on Chromium 140.0.7339.225

  with security patches up to 148.0.7778.96 (plus any distribution patches)

  (source: api)

Qt: 6.11.1



CPython: 3.14.6

PyQt: 6.11.0



Qt wrapper info:

  PyQt6: success

  PyQt5: not imported

  \-> selected: PyQt6 (via autoselect)



colorama: 0.4.6

jinja2: 3.1.6

pygments: 2.19.2

yaml: 6.0.3

adblock: 0.6.0

objc: no

PyQt6.QtWebEngineCore: 6.11.0

PyQt6.sip: 6.15.2

pdf.js: 4.5.136 (/usr/share/pdf.js/build/pdf.mjs)

sqlite: 3.53.3

QtNetwork SSL: OpenSSL 3.5.7 9 Jun 2026



WebExtensions:

  chromium-pdf (mhjfbmdgcfjbbpaeojofohoefgiehjai)

  \[x\] enabled  \[x\] loaded  \[ \] installed

  /usr/share/qt6/resources/pdf



  Google Hangouts (nkeimhogjdpnpccoofpliimaahmaaome)

  \[x\] enabled  \[x\] loaded  \[ \] installed

  /usr/share/qt6/resources/hangout_services



Style: QFusionStyle

Qt Platform: xcb (dwm)

OpenGL: AMD, 4.6 (Compatibility Profile) Mesa 26.1.6

Platform: Linux-6.18.6-gentoo-gentoo-dist-x86_64-12th_Gen_Intel-R-_Core-TM-_i3-12100F-with-glibc2.43, 64bit

Linux distribution: 'Gentoo Linux' (unknown)

Frozen: False

Imported from /usr/lib/python3.14/site-packages/qutebrowser

Using Python from /usr/bin/python3.14

Qt library executable path: /usr/lib64/qt6/libexec, data path: /usr/share/qt6

OS Version: 



\--- /etc/os-release ---

NAME='Gentoo'

ID='gentoo'

PRETTY_NAME='Gentoo Linux'

VERSION='2.18'

VERSION_ID='2.18'



\--- /etc/gentoo-release ---

Gentoo Base System release 2.18



\--- /etc/lsb-release ---

DISTRIB_ID="Gentoo"



Paths:

cache: /home/rado/.cache/qutebrowser

config: /home/rado/.config/qutebrowser

data: /home/rado/.local/share/qutebrowser

runtime: /run/user/1000/qutebrowser

system data: /usr/share/qutebrowser



Autoconfig loaded: yes

Config.py: no config.py was loaded

Uptime: 1:03:52  

**Does the bug happen if you start with `--temp-basedir`?**:

I tried to create a temporary session in temp-basedir, but when I started to duplicate tabs a lot and got over 100, the browser just crashed with no warning. I haven't been able to verify if the bug still happens in temp-basedir sessions.

**Description**

Today I updated my browser version from 6.3.6 to 6.7.0 and my Qtwebengine version from 6.10.2 to 6.11.1 and I am no longer able to load my main browsing session (500+ tabs). It worked perfectly fine before and I never had any issues, but now I am not even able to load it. When I try, the browser freezes entirely and it takes more than 10 minutes to receive another frame again. In this situation the browser either crashes or waits until all the tabs' renderer processors have been killed by the OOM killer, so eventually I am left with a field of errors. I tried enabling lazy restore, but that did nothing. I'll be really thankful if you can tell me how I can potentially fix this problem.

**How to reproduce**

1. Load a browser session with lots of tabs.

2. Notice the browser freeze.

3. Wait for the tabs to get killed and die.

[u/Emergency_Rip_5178]

How is 100+ tabs even usable? How much RAM do you have?

[u/RadoslavL → u/Emergency_Rip_5178]

I have 32 GB and it is absolutely usable. I have not had any serious issues. Wellll, until now.

"Free your mind, Neo" 💖

[u/ElSasori69 → u/RadoslavL]

What do you do that needs more than five hundred tabs?

[u/RadoslavL → u/ElSasori69]

Being neurodivergent and keeping lots of important old tabs for comfort :<