Rated 5 out of 5 stars

https://github.com/tomondev/gmail-manager/blob/master/target/gmail-manager-0.6.4.1.3-tomondev.xpi?raw=true

"Download it. Open Firefox Menu->Add-Ons
There is a button with a gear icon in the top-right of the tab, click it and select "Install add-on from file" and select the xpi file you just downloaded.
Enjoy."

Thanks to Kutt Katrea on the Mozilla forum page for GMM..

Rated 5 out of 5 stars

This Add On is clearly no longer maintained by the Author which is a huge shame as it is one of my favourite Add On's for Firefox.

Several coders have taken it upon themselves to keep it up to date and compatible with the various new releases of FF. It usually takes a day or two for the new XPI files to be made available.

Watch the reviews here for links or follow the forum links in the main page for GMM. The page you want there is currently at #302...

I wish Todd would maintain and update this Add On. I understand why not - things change, people move on. Perhaps it could be released under a Creative Commons licence for people to carry on with? I don't know, I don't know Todd so I can't comment. What I do know is that this is a great Add On - when it's working!

Just because it isn't working for you TODAY doesn't mean it won't work ever again. Watch out for the updated XPI files and you should be fine. Until Firefox gets updated again.

Isn't this FUN?
[no not really]

Rated 5 out of 5 stars

Hey Todd. GMail Manager broke again! I can't log in to Gmail accounts. Could you release the source code for this to, say, SourceForge ??? Then we can keep this updated ourselves?Cheers.

Rated 5 out of 5 stars

Gmail Manager is an important part of my Gmail world. Can you upgrade and / or issue a work around so we can go back to
<3 ing Gmail Manager?

This review is for a previous version of the add-on (0.6.4.1-signed.1-signed). 

Rated 5 out of 5 stars

@WinstonRed You sir, are a god amongst men. It works! Gmail Manager Lives!

Follow these instructions TO THE LETTER.

https://addons.mozilla.org/en-US/firefox/addon/1320/reviews/user:5601928

This review is for a previous version of the add-on (0.6). 

Rated 2 out of 5 stars

I just tried the 0.6.1 release and it doesn't fix the single log in issue. I'll report back as I go for a complete reinstall of Gmail Manager. I really need this to work.

This review is for a previous version of the add-on (0.6). 

Rated 1 out of 5 stars

What happened? I don't recall seeing an update to cause this. It needs fixing soon please!

This review is for a previous version of the add-on (0.6).