Browser Crashes Anki (due to addon). How to solve?

I installed Anki and the “Butler” add-on from the Anki Mastery Course on a MacBook Pro and a Mac Studio (both M1 running MacOS 26.5) over the last couple of days. They are identical installations. The Anki on the Studio works fine but Anki on the MacBook Pro crashes almost every time I open the Browser.

I’ve tried restarting multipule times and finally reinstalled everything from scratch to no avail. I requested help from “The AnKing” support who told me they were surprised at the problem but have provided no help.

I suspect it’s one of the add-ons “Butler” installed but can’t imagine why the problem only appears on the MacBook Pro. Does anyone have any idea what might be going on ?

Thanks, Russ

If it’s a complete app crash, try using the Reset window sizes button in the preferences screen. It helps in some cases especially on macOS.

You can disable any add-ons you don’t need to reduce compatibility issues.

Please also go through the rest of the steps on the Troubleshooting Checklist – Troubleshooting - Anki Manual . That includes advice for how to narrow down which add-on is causing issues.

Thanks for the response, abdo. That doesn’t seem to help in this case. I agree disabling add-ons may help but I don’t have enough experience yet to know which I “need” or even what order I should try in disabling them. I could disable everything “Butler” added but they are all working on the Mac Studio so it seems it shouldn’t be necessary. Presumably they may all be helpful at some point. Anyway, thanks for the suggestion.

They forwarded me your emails and I’m looking into possible add-on issues.

This indicates it’s probably a graphics issue. The link posted by Danika above has info about that. Specifically try switching the Video driver option to “Software” from the Anki → Preferences.

i get a similar crash and others
specifically with regards to the browser when I open the app and directly open the browser, the app crashes.

Other times, it’s for some other reasons I haven’t been able to pinpoint.

these are crash reports for other reasons. i could not paste it here coz it was too long

https://chat.deepseek.com/share/nzp4u3gnk2mjaorsfs

QT_ACCESSIBILITY=0 /Applications/Anki.app/Contents/MacOS/Anki
using this in terminal caused the app to stop crashing

also no crash when anki is launched with shift held

This makes me suspect the crash is caused by the interaction between one (or more) add-ons and Qt’s accessibility framework, rather than by Anki itself or my collection.

My issue did not resolve by changing video driver

Just an update on my investigation:
I used AI to help analyze the crash reports, which pointed me toward Qt’s accessibility layer as the likely source of the crashes.
Initially, crash reports indicated BetterTouchTool (BTT) was responsible. However, after disabling BTT, Anki still crashed. Looking at newer crash logs, I found that Lasso was now the process interacting with Anki’s accessibility APIs.
Quitting Lasso completely resolved the issue, and Anki now launches normally.
This suggests the crash is related to Qt’s accessibility layer interacting with third-party accessibility/window management apps.
I’m not certain whether an add-on is also involved, but I wanted to share these findings in case they help someone else troubleshoot a similar issue.

Hi abdo,

Thanks for the response. I tried the video driver suggestion and it didn’t help in my case either. Please keep me posted on any progress you make, and thanks !

Russ

Thanks salman. If I stumble on anything useful, I’ll definitely report it here. abdo is investigating and will hopefully find the issue. Good Luck, Russ

Are you getting any error messages similar to the ones posted by @salman?

Hello salam and abdo,

abdo, I don’t get error messages other than the crash report which you now have.

abdo and salam, I think I found something. I had already tried everything in the troubleshooting checklist suggested by Danika_Dakika above except the add-on process of elimination. I’ve done that now and the “Auto Highlight Cloze in Browser Fork by Shige” add-on seems to be causing the problem in at least my case. After disabling it (and leaving everything else enabled), I’m not seeing the crash anymore.

Obviously, that’s not a solution - what is it doing to cause that ? - and it sounds pretty useful so I’d like to have it, but disabling it for now seems to be a temporary solution. If anyone knows how to reach “Shige” perhaps he can update it ?

fwiw - Russ

Author is here (@Shigeyuki) but it’s unlikely the add-on can do anything to fix such crashes, as they are usually caused by deep bugs in Qt/Chromium libraries which Anki is built on.

Hi abdo,

Ok, understand. I’ll hang to see if you discover anything in your investigations.

Thanks, Russ

Hi thanks for the report, I’ve added a workaround so please try updating the add-on. (Tools → Addons → Check for update) But this bug hasn’t occurred on my device so I’m not sure if it’s been resolved, if the problem persists please contact me again.

Hi Shigeyuki,

Thanks for the super fast response. I re-enabled and updated the add-on and that seems to have stopped the crashing. I’ll report back if I see any more of them.

Thanks again, Russ

I’m curious what was the fix?

I’m not sure yet, this bug only occurs on macOS but I don’t have macOS right now so I can’t debug it. So I added some code to all the suspicious parts, probably one of them is working but I don’t know which one. Also another user said this bug doesn’t occur sometimes so I’m not sure if it’s been completely resolved or not. I use a Mac occasionally so I plan to look into it when I do.

Edit:

Specifically it looks like this:

  1. Check if numberOfMatches in QWebEngineFindTextResult is not 0
            if matches.numberOfMatches() <= 1:
                return
  1. Check if AnkiWebView has already been deleted
        if not _is_webview_valid(webview):
            return
  1. Enclose some other functions with try-except and return if an error occurs.