Theme Font and Size Changer—what's up with it now?

TF&SC stopped working with Thunderbird this morning. I’ve tried several ways to download and install the newest version 64.1—reinstalling, restarting, deleting older files over and over, but nothing has worked and I’m stuck again with that ridiculously small font in the message list pane. TBird 52.7.0, Mac desktop, OS 10.13.3

Help? Thank you!

Nothing changed in Thunderbird to cause this. The add-on just likes to expire itself - again.

From the workarounds list at See there is a non-expiring version of the addon…

On right+click the “get it here” link to save the XPI file to disk. Then in Thunderbird in tools > addons click the gear to “Install Add-on From File”


Thank you, wsmwk! Appreciate the prompt solution!

Hi, I have a 52.7.0 version of thunderbird on macbook pro. Since a few days, the TF&SC add add on stopped working. I’ve downloaded the non expirer version, and installed from disk, but to no avail. I still cannot figure out how to make that thing work again and am stuck with this stupid small fonts in Thunderbird. What am i doing wrong?

Awesome! Thank you very very much! It worked just great.

There is also … which works on version 60

I see that the Theme Font and Size Changer is not compatible with Thunderbird 68.0 for Windows. Is the code being updated/changed to allow the add-on to work with the latest version of Thunderbird?

Theme Font and Size Changer (fixed) is compatible up to version 65.0 and has a Support Email link on the page. You will have to ask the developer of the extension.

Theme Font and Size Changer (fixed)