Can't enable Dark/Light theme on TB 78.5.0

[hopalongrock]

Using TB 78.5.0 on Windows 10

I just wanted to try how looks the builtin dark or light theme, but I have no success.



I click on Enable button in the Themes section of Add-ons Manager, but the theme remains (disabled), nothing happens.

What else do i need to do?

[tanstaafl]

All I need to do is click on the enable button for the theme. Try temporarily disabling any extensions you have, restart Thunderbird, and try again.

Some people report problems with how the dark theme looks due to their choice of Windows theme but that would be a different problem.

[hopalongrock]

I clicked Enable, nothing.

I restarted with addons disabled, clicked Enable, again nothing.

The same happens in case of Light theme.

[morat]

Try exiting the app and using the -purgecaches command line option.

i.e.

thunderbird.exe -purgecaches
ThunderbirdPortable.exe -purgecaches

[hopalongrock]

Unfortunately it doesn't help.

[tanstaafl]

Somebody in https://support.mozilla.org/en-US/questions/1310664 had the same problem with 78.4.0 . They solved the problem by uninstalling and re-installing.

[hopalongrock]

Thanks, this helped me, probably my profile causes this.

I have a separate installation instance for test, now both updated to 78.5.0.
The test (now offline) profile is originally a copy of my working TB profile.

In this test instance (profile) I can Enable the dark mode.

Because I only wanted to see how the dark mode looks, I don't do anything now.