New crash on Ubuntu 26.04 (segmentation fault) on sync

Anki Help
1

Anki has been running without fault for ages here, but just today it has started crashing on startup. The graphical interface briefly appears, but then crashes before any interaction is possible.

When I start Anki from the command line, it looks like this:

pinnerup@ergi:~$ anki
Starting Anki 26.08.1...
Wayland support is disabled by default due to bugs:
https://github.com/ankitects/anki/issues/1767
You can force it on with an env var: ANKI_WAYLAND=1
2026-09-10 19:17:37,351:INFO:aqt.mediasrv: Serving on http://127.0.0.1:45001
MESA-INTEL: warning: Haswell Vulkan support is incomplete
MESA-INTEL: warning: Haswell Vulkan support is incomplete
Starting main loop...
Segmentation fault         (core dumped) anki

When I start Anki with anki --safemode, it seems to work fine and I can review cards, but as soon as I press the “Sync” button, Anki crashes.

Interestingly, Anki also crashes after a few seconds if I just place the cursor on the “Sync” button without clicking it.

I have not upgraded Anki recently prior to this crash popping up, but I’ve checked now with Anki 26.08.1 and the new 26.09b3, and both show the same behaviour. I’m running Ubuntu 26.04 (Linux 7.0.0-31-generic).

2

We got some reports of graphics issues on Linux/macOS since 26.05

Have you tried switching to a different video driver from Preferences?

3

Unfortunately it seems Anki also crashes as soon as I try to open Preferences (or press CTRL+P), so I am unable to access the video driver setting.

So far I’ve tried 26.05, 26.08, 26.08.1 and 26.09b3 (all installed manually via the provided tar.zst files), and all yield the same result. Even if I create a new (blank) profile without synching anything, it won’t let me open the Preferences.

Interestingly, I’ve just tried uninstalling all of these manually installed versions and instead installing the package ‘anki-desktop’ via snap, and it works.

When I run it, I get:

pinnerup@ergi:~$ anki-desktop 
Starting Anki 26.08.1...
Wayland support is disabled by default due to bugs:
https://github.com/ankitects/anki/issues/1767
You can force it on with an env var: ANKI_WAYLAND=1
Gtk-Message: 19:37:59.625: Failed to load module "canberra-gtk-module"
Gtk-Message: 19:37:59.628: Failed to load module "canberra-gtk-module"
2026-09-11 19:37:59,914:INFO:aqt.mediasrv: Serving on http://127.0.0.1:43505
Qt info: Sandboxing disabled by user. 
MESA-INTEL: warning: Haswell Vulkan support is incomplete
MESA-INTEL: warning: Haswell Vulkan support is incomplete
libva error: /snap/anki-desktop/91/gpu-2404/usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so init failed
Starting main loop...
conf key heatmap should be fetched with col.get_config(), and saved with col.set_config()
conf key heatmap should be fetched with col.get_config(), and saved with col.set_config()
conf key heatmap should be fetched with col.get_config(), and saved with col.set_config()
2026-09-11 19:38:12,829:WARNING:waitress: unhandled close event

It seems to work no matter what video driver I choose in “Preferences”.

4

You can also change it without opening Anki by modifying the gldriver6 file: Display Issues - Anki Manual

Looks like the Snap package uses an older version of Qt (6.10 while the official build is on 6.11) so it’s not affected, or there might be other factors in play.

6

I encountered a very similar issue with Anki 26.09.3 on Fedora 44, using an NVIDIA RTX 3080. Figured I’d share what worked for me.

Problem description

Anki would segfault shortly after opening. Running it with QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu" anki --safemode allowed it to open, but it would still segfault whenever I tried to sync.

After investigating the core dump with coredumpctl, the crashing thread showed:

#4 FcCharSetFindLeafForward (libfontconfig.so.1)
#5 FcCharSetHasChar (libfontconfig.so.1)
#6 QFontEngineMultiFontConfig::shouldLoadFontEngineForCharacter (libQt6Gui.so.6)
#7 QFontEngineMulti::stringToCMap
#8 QTextEngine::shapeText

This pointed to a Fontconfig-related crash rather than directly to the NVIDIA driver.

What solved the problem

Rebuilding the Fontconfig cache fixed the problem for me:

mv ~/.cache/fontconfig ~/.cache/fontconfig.backup-$(date +%s)
fc-cache -r

After running these commands, Anki started working again, including synchronization.

This may be related to a recently reported Chromium 154 issue where incompatible Fontconfig cache files cause crashes in Qt applications: Chromium. Or not, I’m not sure, but the stack trace matches the reported issue closely.

Posting this in case it helps others experiencing similar crashes.