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is there a way of reverting back to previous firefox version

  • 3 vastust
  • 4 on selline probleem
  • 1 view
  • Viimati vastas TonyE

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I use firefox extensively for development. I use firebug and dojo. It seems that the new version (Firefox 4) is far slower than the previous version and sometimes hangs completely. I believe this may be caused by Firebug doing a lot of work but it never used to happen. Also firebug doesn't quite seem to work as well with dojo script. Previously if you did a dojo.require to drag in a js script file then you could automatically see it through firebug. Now have to put files I want to debug with script tags. Is there a way of reverting back to previous firefox version?

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To downgrade to Firefox 3.6 first uninstall Firefox 4, but do not select the option to "Remove my Firefox personal data". If you select that option it will delete your bookmarks, passwords and other user data.

You can then install the latest version of Firefox 3.6 available from - it will automatically use your current bookmarks, passwords etc.

To avoid possible problems with downgrading, I recommend going to your profile folder and deleting the following files if they exist - extensions.cache, extensions.rdf, extensions.ini, extensions.sqlite and localstore.rdf. Deleting these files will force Firefox to rebuild the list of installed extensions, checking their compatibility, and reset toolbar customizations.

For details of how to find your profile folder see

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Thanks for that. Assume will need to then reinstall plug ins. Is there a way of coexisting versions. I.e will want to test against ff4 also once everything ironed out using the faster previous version.

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No need to re-install plugins or extensions.

You can install them both but there are a few steps to take.

When you install the second version of Firefox use the custom installation option and choose a different location to install Firefox.

In order to use both versions, you need to create a new profile for the second version of Firefox (Firefox stores user data in the profile). Using the same profile with different versions can cause problems. Once you create a new profile you can copy certain data such as bookmarks and passwords between them. You can also use Firefox Sync to keep the profile synchronized. Finally, you will need to set up shortcuts to launch the correct profile for each version.

The following links show how to do this:

An alternative way of testing Firefox 4 is to install the portable version on your hard drive. It will use its own profile folder and not interfere with the other version of Firefox. You can get the portable version from