This article describes how to install a previous version of Firefox, a process also known as "downgrading". For instructions on how to install a newer version, see Uppdatera Firefox.

Problems after upgrading Firefox are generally not caused by the new version itself, but rather the upgrade process. Installing a previous version will not help for most problems. Some common issues include:

• Can't access websites anymore
• "Firefox can't connect securely..." error

Other problems can be solved by creating a new profile.

If you find none of these things work and you still want to downgrade to a previous version, you can do so by downloading and running a previous version's installer.

Installing Firefox 3.5.x

The latest updates to Firefox 3.5 are made available here.

Previous versions

Previous versions of Firefox have public security problems. You could be exposed to viruses, phishing, and other attacks by running old versions.

1. Go to the Mozilla FTP server.
2. Choose the version you want.
3. Choose the win32/mac/linux-1686/ folder
4. Choose your language. en-US is US English.
5. Choose the file that does not end in .asc. The download will then start.
6. Once the file is downloaded, install it.

After downgrading, if you intend to stay with that version, you will need to turn off Software Update. It is highly recommended that you try new versions of Firefox as they're released to see if they solve your problem.