For example, the Windows registry or other installed programs may expect Firefox to be in the default location (e.g., C:\Program Files\Mozilla Firefox or C:\Program Files (x86)\Mozilla Firefox on 64-bit Windows). You can install Firefox in the same location to minimize any side effects. Make sure to remove the Firefox installation directory. Versions that end in b (e.g., 19.0b6) are Beta releases, intended for users who are testing pre-release versions. 0.3esr) are Extended Support Release versions intended for organizations. Release versions that end in esr (e.g., Firefox 17.

Download the version you want from or Note: If you are looking for an older version of a Firefox 'final' release, look for a download with no letter suffix (e.g., 18.0.2 is the last final release version previous to 19.0).To downgrade to an old version of Firefox, back up your Firefox profile first, as a precaution, and then follow these steps: