Firefox 67 Cannot Connect After Update on Ubuntu 18.04

18.04browserfirefox

I have been using Firefox on Ubuntu 18.04 for several weeks. I currently have firefox 67.0 (freshly updated).
Since the update, firefox cannot connect to the internet anymore.
The internet is working fine. I am writing this post from the Opera browser the I installed on Ubuntu 18.04 after the problems with Firefox.

I tried to follow the suggestions of this post. Explicitly I tried the following:

  1. Change proxy setting, in about:preferences Network Settings. I tried the options "no proxy", "Auto-detect proxy" and "Use system proxy" (the latter was the default).
  2. In about:config I set the "network.dns.disableIPv6" to TRUE
  3. In about:config I set the "network.dns.disablePrefetch" to TRUE

The issue seems firefox-specific. Opera does not give any problem. Pinging to www.google.it works fine (so no DNS problems).

I am fine using Opera, but I would also like to understand hwo to fix the issue in Firefox!

Best Answer

The easy fix, with no profile or preferences rebuilding required...

This just renames the current Firefox cache folder. Firefox recreates this folder at next launch. The .HOLD only saves the old folder as a backup, just in case there's something there that the user still wants to manually save... but it can probably just be sent to the trash.

  • start Firefox v67.0
  • go to about:profiles
  • note the name of the current profile
  • quit Firefox
  • start Files
  • control+h to enable viewing of hidden files
  • go to ~/.cache/mozilla/firefox
  • rename the current profile folder to xxxx.default.HOLD
  • restart Firefox
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