Fontconfig error stops pre/review

Anki Help
1

so (yes --safemode, and newest anki version), reviewing, or trying to preview a certain tag ( BlutImmun- &_lymphatisches_System) in the shared deck (Ankiphil - Vorklinik) does not work.

In the preview window it does’t load the card, and you can’t suspend the card or do anything else.

In the reviewer the screen turns blank.

I have tried opengl as well as software video driver.

The error I get when trying to preview is:

Fontconfig error: Cannot load default config file: No such file: (null)

2

I can’t find that error in Anki anywhere. If you’ve ruled-out it being an add-on, are you sure this is coming from Anki?

Go to Help/Anki > About – click “Copy Debug Info” – paste that entire result here when you respond.

1 Like
3

fontconfig is actually a library related to fonts (see fontconfig). This is used on linux, though I’m not sure if other OSes use this library too. It’s not coming from anki. I might only know little about fontconfig, but I cannot imagine fontconfig to be the issue here.

Does that mean it works for other decks or tags? If so, are there any apparent differences between the ones that work and those that don’t?

In addition to the request from danika, I’d like to ask you to sent the entire terminal output in the chat. Maybe there is is something else that might give us a clue.

Also: how did you install anki?

1 Like
4

I have the same problem
Debug info in safe mode

Anki 25.02.4 (a5c33ad0)  
Python 3.9.18 Qt 6.6.2 PyQt 6.6.1
Platform: Linux-6.14.3-arch1-1-x86_64-with-glibc2.41

Terminal log

~ ❯❯❯ anki --safemode
Anki starting...
Initial setup...
Starting Anki 25.02.4...

(anki:146804): Gtk-WARNING **: 05:11:19.414: Theme parsing error: colors.css:86:1: Invalid name of pseudo-class
2025-04-28 05:11:19,577:INFO:aqt.mediasrv: Serving on http://127.0.0.1:33253
Starting main loop...
JS warning /_anki/js/vendor/mathjax/tex-chtml-full.js:1 No version information available for component [tex]/noerrors
JS warning /_anki/js/vendor/mathjax/tex-chtml-full.js:1 No version information available for component [tex]/mathtools
Fontconfig error: Cannot load default config file: No such file: (null)
JS error /_anki/legacyPageData?id=131704070061792:50 Uncaught ReferenceError: pycmd is not defined
onclick handler needs to return false
JS error /_anki/legacyPageData?id=131704070061792:41 Uncaught ReferenceError: pycmd is not defined
onclick handler needs to return false

The JS errors are irrelevant (I also have them with the cards that don’t cause this)
From the error onward you can’t enter any deck (which are these two errors)

JS error /_anki/legacyPageData?id=131704070061792:50 Uncaught ReferenceError: pycmd is not defined
onclick handler needs to return false
JS error /_anki/legacyPageData?id=131704070061792:41 Uncaught ReferenceError: pycmd is not defined
onclick handler needs to return false

I faced this with one particular card and I don’t have this problem with other cards that use the same Note type
I face the error in reviewer after showing answer

5

Anki 25.02.4 (a5c33ad0)
Python 3.9.18 Qt 6.6.2 PyQt 6.6.1
Platform: Linux-6.14.4-arch1-1-x86_64-with-glibc2.41

6

Downloaded the tar file and ran the the install script

Anki starting...
Initial setup...
Starting Anki 25.02.4...
Wayland support is disabled by default due to bugs:
You can force it on with an env var: ANKI_WAYLAND=1
2025-04-28 08:38:28,398:INFO:aqt.mediasrv: Serving on http://127.0.0.1:42681
Starting main loop...
JS warning /_anki/js/editor.js:439 No version information available for component [tex]/noerrors
JS warning /_anki/js/editor.js:439 No version information available for component [tex]/mathtools
blocked main thread for 238ms:
  File "<string>", line 1, in <module>
  File "aqt", line 573, in run
  File "aqt", line 787, in _run
  File "aqt.browser.sidebar.tree", line 344, in mouseReleaseEvent
  File "aqt.browser.sidebar.tree", line 452, in _on_search
  File "aqt.browser.sidebar.tree", line 301, in update_search
  File "aqt.browser.browser", line 496, in search_for
  File "aqt.browser.browser", line 505, in search
  File "aqt.browser.table.table", line 190, in search
  File "aqt.browser.table.model", line 260, in search
  File "aqt.browser.table.model", line 274, in _search_inner
  File "aqt.browser.table.state", line 159, in find_items
  File "anki.collection", line 667, in find_cards
  File "anki._backend_generated", line 1670, in search_cards
  File "anki._backend", line 168, in _run_command

Fontconfig error: Cannot load default config file: No such file: (null)o