Firefox Community Forum

I have a custom theme enabled on my browser. Every time I log into Firefox on a shared university computer my theme is turned off for that desktop aswell as my personal laptop. I have to manually enable it on my personal devises again each time after using school computers. Is there a way to prevent this?

As above themes not working on latest version of firefox difficulty reading menu & tabs bar as light blue needs to be dark coloured

Also have difficulty reading your website because of white background will not work on dark mode retinopathy burn

Hi, I rebooted Firefox today because a website was frozen, and when it came back, it was asking for a troubleshoot or just continue, and I don't know exactly what that meant, but when I clicked on refresh, everything was changed, including the theme. And then when I tried to restore the theme back to the original it said, add-ons are disabled by safety, and I don't know what that means, and it's not explaining how to undo it. And now everything looks different and I'm not happy with it, and it's not really letting me add any other themes, and if I add them, they don't seem to fully load, the page still looks all white

Best regards,

At the beginning of 2025, I created a private theme and installed it locally (Windows 10), consisting of a manifest.json and a GIF file. It worked perfectly. Now, on Windows 11, I'm trying to use the theme again, but when I upload the file (.zip or .xpi — via about:addons -> Install Add-on From File), I always get the message that the file is corrupted. However, if I test it temporarily under about:debugging, it works immediately without any issues.

I would really appreciate a solution! <3