Cannot download addons in Firefox 3.5 using Karmic Koala.

Asked by Wes on 2009-12-28

I have performed a clean install of ubuntu 9.10 on a dual boot machine (with XP).
I found that I am no longer able to add extensions under Tools->Add-ons in FireFox 3.5.6. Interestingly, I am able to install the extensions using the ubuntu software centre. I have tried to run Firefox as root using 'gksu' but it did not help. This was not an issue in jaunty. Many thanks.

P.S. I love ubuntu ! :)

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GeorgeVita (8-launchpad-mhnyma-com) said :

Hi Wes,
I just tested my firefox 3.5.6 on Ubuntu 9.10 and everything seems to be OK.

The possible 'misunderstanding' is that from Tools > Add-ons > Extensions tab you can handle installed 'add-ons' (enable/disable/uninstall/preferences)
... but to ADD them you can use 'Get Add-ons tab'!

Try the following: Tools > Add-ons > Get Add-ons
type 'YSlow' into the 'Search All Add-ons' field and press <ENTER>
click on YSlow title and then on 'Add to Firefox', after some seconds the s/w installation window will let you 'Install Now'.

Restart Firefox and check from Tools > Add-ons > Extensions tab that is already there.


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Sam_ (and-sam) said :

> to run Firefox as root using 'gksu'
Please never run Firefox with elevated permissions.

Does addon installation work from here:

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Wes (w06245) said :

Thanks GeorgeVita and Sam for the amazingly quick response. :)

I was able to add extensions using Tools>Add-ons>Get Add-ons without any issues using FireFox 3.0 or 3.5.6 under Jaunty.

When I tried the same procedure under Karmic, the initial load time for the extension to show the 'install now' popup becomes very slow and when I press install it would continue to struggle and returns with a 'Download error' error message. I have a laptop with jaunty and firefox 3.5 installed and the add-ons process worked perfectly.

Error message when trying to install the add-0ns:
Firefox could not install the file at

because: Download error

I have tried to use 'gksu' but the issues still persist.

I have a gut feeling maybe it has something to do with security settings under Karmic as in Jaunty I did not have to put in my password to install software under the add/remove application. Also the process worked if I added the extension/s through the 'ubuntu software centre'.

Its been a bit of a struggle trying to get Karmic to work but I am learning a lot about Ubunutu/Linux in the process. :) Again, many thanks.

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Sam_ (and-sam) said :

About -228

You could make a cut, close Firefox, rename .mozilla, restart Firefox.
mv .mozilla .mozilla.broken

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Wes (w06245) said :

Hi Sam,

Thanks for the help but it is not working and I will be moving but to Jaunty for now. Many thanks.

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Wes (w06245) said :

Sorry I meant I will be reinstalling Jaunty. Much more stable for my machine. Cheers.

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mikeallora (mike-woche) said :


I update my browser firefox and the extension Yslow two days ago. And now when i start firefox, this one open and crash in the same time.

So i can't use it, he crashes at the start, so i have to use chrominium or opera browser.

I can't do anything, but just click on the icon to see the browser one second and after he crashes.