Hi

Thank you for your question. I use Ubuntu myself (16.04) with an early pre-release version of Firefox, so I was interested to have a look into this. I have tried to recreate this myself and could not, which leads me to believe that i think I know what may be happening.

For many well known Linux distributions, there are two versions of Firefox: the version you can download from Mozilla (a "Mozilla build") and the one provide with or by your Linux distribution (a "distro build"). This is because some distributions like to package Firefox for their distribution, but in doing so create a version that is fundamentally the same, but will have one or two little differences.

There is nothing "wrong" with using a distro build. It is still at its core the same Firefox we all love, and we do our best to help support it here, but it was not published by Mozilla.

You may want to move to a Mozilla build. Make sure you have your Firefox profile backed up (more info here), before download and opening a Mozilla build from here.

The other approach you may wish to take is to refresh Firefox. You can read more about how to do this here.

I hope this helps, but if not, please come back here and we can look into a different solution for you.

Hello and thank you for the help, I backed up my data, I completely uninstalled firefox, downloaded the latest version from the mozilla website, I try it and it works just fine, I put back my personal data to the folder where they should be and the problem comes back, so the problem is there, maybe I should try to put the data back one folder at once, to see where the problem lies, maybe it has nothing to do with the distro version but i like mozilla build, i wasn't aware of this difference eventhough i noticed that you can't update FF from the update preferences So thank you very much for your help, have a nice day