# firefox suddenly refused to start as non-root user

## toralf

[same happend for thunderbird too]

The issue suddenly appeared and went away - I'm convinced it is worth to be evaluated. I rebooted a hardened stable Gentoo (installed in December 2014) after an uptime of 7 days. Updates were made daily, user environment is KDE 4.11.3

After the reboot neither Firefox nor Thunderbird could be started, the error message was "cannot open profile directory". As root however 

```
$>xauth merge /home/tfoerste/.Xauthority;  sudo -u <common user> firefox
```

 worked however. There were no other issue with creating/deleting files. Moving away of ~/.mozilla and ~/.thunderbird even doesn't help nor any "-safe-mode", "-profilemanager" as starting parameter. I started to revert all package upgrades since last boot (29th of December), beginnning with libical (kdepimlibs was re-emerged too due to dependiencies) - no luck. Stopped that attempt in favor of booting a stable gentoo sources, no success.

Rebooted back to the hardened kernel (3.1.7.7-r1) and added the user to the group "video" (via 

```
usermod -a -G video tfoerste
```

  - issue went away !

Removing the group video from the user via manual editing /etc/group - firefox and thunderbird started now fine too.

So - what was the culprit ??Last edited by toralf on Tue Jan 06, 2015 10:27 am; edited 4 times in total

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## Apheus

I suspect 3D acceleration. Firefox settings - Advanced (last tab) - General - Use hardware acceleration. If turned off, firefox doesn't use 3D graphics for the UI. I don't know if this affects web content too. Maybe you would have to turn off webgl in about:config.

But having the user in the "video" group is the right way to do it. I have no clue how/why it works even after you removed the user from the group.

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## toralf

Hhm - 3D- accelaration isn't an option in Thunderbird, which refused to work too with the same error.

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## Apheus

In thunderbird it is hidden in the config editor (thunderbird's "about:config"): The preference is "layers.acceleration.disabled" in both firefox and thunderbird. Default is "false": Acceleration is enabled by default.

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