This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

[94.0] Unable to load/Corrupt theme.xpi from color.firefox.com

more options

Custom theme from color.firefox.com fails to install from "Install Add-on From File_" in about:addons after exporting it as theme.xpi from color.firefox.com

Error message: This add-on cannot be installed because it appears to be corrupt.

Theme XPI file: https://cdn.discordapp.com/attachments/150721173305425922/906300644405702706/theme.xpi

Custom theme from color.firefox.com fails to install from "Install Add-on From File_" in about:addons after exporting it as theme.xpi from color.firefox.com Error message: This add-on cannot be installed because it appears to be corrupt. Theme XPI file: https://cdn.discordapp.com/attachments/150721173305425922/906300644405702706/theme.xpi

All Replies (4)

more options

Delete the file. Then download it again.

more options

That is probably because the file isn't signed (no META-INF folder). I can load the file via the about:debugging page as a temporary add-on.

You can check the Browser Console for possible error messages.

more options

It is possible that the Firefox Color extension can handle such an unsigned theme file.

more options

1. Been there done that, Temporary add-on means I have to manually load a theme each time i start the browser. 2. An add-on for a theme I thought that could be installed painlessly like the few stock ones that already exist... I guess that's where it is for now.

I was not looking for an alternative, but thank you for pointing out to the signature part; I've submitted the theme on AOM, awaiting review.