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Thunderbird randomly changes to dark mode

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I'm running v102.6.0. on Win10 v22H2. I have default Windows mode set to Light and default app mode set to Light. I have Thunderbird theme set to Light. Thunderbird randomly changes to "dark". Thunderbird Themes still shows Light "Enabled" If I disable Light, it changes back to system mode and is light which I assume is following the Win 10 default app mode of Light. It may stay this way for a day or so, OR sometimes it changes back to dark after only a few seconds, minutes, or hours. If I set the TBird theme to light again, it changes to light and then the cycle repeats. Dark mode is frustrating to use. The top menu bar is so dark on the right side that the tabs and the "Minimize", "Restore Down", and "Close" "buttons" are not visable. Any suggestions? Am I the only one with this problem? This started a month or so ago probably after an update but I don't know for sure and I don't know what version I was running before this started. Help!!

I'm running v102.6.0. on Win10 v22H2. I have default Windows mode set to Light and default app mode set to Light. I have Thunderbird theme set to Light. Thunderbird randomly changes to "dark". Thunderbird Themes still shows Light "Enabled" If I disable Light, it changes back to system mode and is light which I assume is following the Win 10 default app mode of Light. It may stay this way for a day or so, OR sometimes it changes back to dark after only a few seconds, minutes, or hours. If I set the TBird theme to light again, it changes to light and then the cycle repeats. Dark mode is frustrating to use. The top menu bar is so dark on the right side that the tabs and the "Minimize", "Restore Down", and "Close" "buttons" are not visable. Any suggestions? Am I the only one with this problem? This started a month or so ago probably after an update but I don't know for sure and I don't know what version I was running before this started. Help!!

All Replies (5)

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re :Dark mode is frustrating to use. The top menu bar is so dark on the right side that the tabs and the "Minimize", "Restore Down", and "Close" "buttons" are not visable.

I came across a similar situation not long ago. In that situation they checked the following to fix the problem. The user had settings to use the System colours and System theme.

Check the following:

  • Menu icon > Settings > General
  • Under 'Language & Appearance'
  • Fonts & Colours' - click on 'Colours' button
  • Set 'Text' to 'Black'
  • Set 'Background' to 'white'
  • Do NOT select - leave unchecked - 'Use System colours'
  • Override the colours specified....... set to 'Never'
  • Click on 'OK'


  • Menu icon > Addons & Themes > Themes

There are 3 default themes usually available:

  • Light - a theme with a light scheme
  • Dark - a theme with a dark scheme
  • System theme -auto - follow the operating system for buttons,menus and windows

You need to have 'Light' set as Enabled. If it is not enabled then click on 'Enable'.

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Thanks for getting back to me. The settings you suggested are what I currently have. I checked them again and nothing has changed. What seems weird is that Thunderbird is dark though the Light theme or system theme shows enabled. This has been an issue through several Thunderbird updates. I keep hoping that an update will solve the problem. Win 10 also updated once while this has been an issue for me and that didn't help either.

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One other additional piece of info. The top border is not a consistent shade of black from left to right. The left side is much lighter than the right. I have set the theme to Dark just to see what it look like and it is different than what I am seeing when it changes to what I am calling "Dark mode". From that I would say it's not actually changing to Dark theme, but the Light theme and system themes just go dark for some reason.

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What's the setting for hardware acceleration in Settings/General (bottom of tab). If it's enabled, disable it and restart TB, and see if there's a difference.

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Thanks for your suggestion. I tried disabling hardware acceleration. Unfortunately, it didn't solve the problem. I don't really see any differenceat all, so for now I'm just leaving it at that setting.

Any other ideas?