martt

You might read much about Firefox Profiles on this forum ...and certainly the Mozilla forum. "Have you tried a new Profile?" or "Try a new Profile" is often seen in posts. That's because the condition of the Profile affects the performance of Firefox perhaps more than any other aspect of it. Even so, the Profile often gets overlooked when trying to get Firefox working properly. Reinstallations/upgrading are common when trying to fix a fault in Firefox but this has no effect on the all-important Profile. It remains unaffected by reinstalling or upgrading.

When Firefox 2.0 is installed, it will grab hold of and use the Profile created by Firefox 1.5 (or earlier) if it is present. The only ways of avoiding this is to either to manually delete the Profiles folder before reinstalling or upgrading and let Firefox automatically create a new one, or manually create an additional (new) Profile and select it as Firefox starts up.

Sometimes Profiles go wrong or, if it's an old Profile, it may not work properly for one reason or another when asked to work with a newer version of Firefox. This can certainly be the case with extensions or themes present within an existing Profiles Folder. These may not only be troublesome in as much as they don't work properly. They might also affect Firefox's workings generally. Also, since so much goes on inside the Profiles Folder, it can give trouble due to other components not working. In view of that, trying a new Profile whenever any sort of devious fault occurs is perhaps the first thing to do when tracking it down.

An additional Profile is easy to create and try. If a fault clears up when using a new Profile, one of two courses can be taken:

1. Keep the Profile and build it up to requirements by reinstalling extensions and themes. Previously made backups may work well when re-building a Profile but for a thoroughly clean start, reinstall them afresh from the Mozilla Add-ons site. You can copy your bookmarks file (Bookmarks.html) from the old Profiles folder into the new one.

2. Now that it's clear the problem is being caused by something in the Profile, work on the original one to find out what the cause is. For example: Delete the 'localstore.rdf' file, disable extensions and themes, clear the cache etc. These steps can alternatively be tried before trying a new Profile if desired.

On the other hand, if the new (additional) Profile makes no difference to a fault, it can then be deleted and the original Profile will still be in place for Firefox to use. Now that the possibility of a Profiles Folder fault has been eliminated, the fault can then be looked for elsewhere.

Mozilla has made available a page called 'Standard diagnostic'. This gives step-by-step measures to go through when Firefox refuses to work properly. The above isn't so comprehensive as this but does mostly work. I personally prefer to create a new Profile and reinstall extensions as a matter of course whenever a major update is released. I find this keeps Firefox running as smoothly as possible.

There's an interesting Mozilla page here. If you scroll down to the 'Files' heading, it gives the names of files in the Profiles folder and a description of what they do. I don't think any file names have been changed over the years. I expect those who help develop the browser and know it inside out have got used to them and might be upset if they were changed. Not so good if you're trying to find a particular file for the first time though.