About the Firefox Profiles Folder.

*

The Firefox Profiles folder contains: Bookmarks - Passwords - Themes - Extensions - Customisations - Download Manager. Here is a complete list of files in the Profiles folder and a description of what they do. The files are numerous and they perform essential functions.

*

Many Firefox faults originate in the Profiles folder.

*

A fault in the Firefox Profiles folder won't be cured by uninstalling Firefox and then reinstalling it unless the box marked 'Remove my Firefox personal data and customisations' is ticked in the uninstall options. When ticked, the Profiles folder and the contents will then be deleted as part of the uninstallation procedure. Any faults residing in the Profiles folder will therefore also be removed. When Firefox is reinstalled, a new Profile will be created.

*

Re-installing Firefox (without first uninstalling as above) won't cure a fault in the Profiles folder.

*

Purely re-installing Firefox doesn't create a new Profile or overwrite an existing one.

*

A major Firefox upgrade may update the Profiles Folder but many of the files within the folder remain the same ones as before.

*

In short, a Profile that was automatically created by Firefox when it was initially installed, lasts until it is manually removed.

*

An old Profile (perhaps one that's been used version after version), could arguably be suspected of causing a fault more than a newer one.

*

Some Extensions or Themes stored within the Profiles folder might cause Firefox not to work properly.

*

Extensions that are incompatible with a newer version of Firefox might also affect its operation.

*

The Profiles Folder can give trouble due to other files/components not working or being corrupt.

Firefox fails to work as expected:

Reinstalling Firefox can of course be tried. However, something amiss in the Profiles folder is more likely to be the cause of the problem. There are a number of steps that can be used to determine if a fault might lie in the Profiles folder. Here are some:

a)

Start Firefox in Firefox's Safe Mode to see if the problem clears. Safe Mode runs Firefox without extensions and themes enabled. Faulty extensions, or extensions that conflict with each other, can be a cause of troubles in Firefox. Some themes may also cause an unexpected display. So, if the a fault doesn't occur while Firefox is running in Safe Mode, the cause is likely to be a troublesome extension or theme.

b)

If Firefox runs correctly in Safe Mode, start Firefox normally and tie down the troublesome extension by disabling them one by one in the 'Extension Manager' until the fault clears (go to: 'Tools > Add-ons'). Closing and restarting Firefox may be necessary for any changes to take effect.

c)

If toolbar and/or Window size preferences keep resetting to the default settings, perhaps delete the ' localstore.rdf' file (located in the Profiles folder). An alternative cure for this problem is to Start Firefox in Firefox's Safe Mode (shortcut in the 'Start' menu). A dialogue box with some tick-boxes will open. Select 'Reset toolbars and controls' (only). Click the button that says 'Make Changes and Restart'. When Firefox opens, it will be necessary to set preferences/customisations again but settings should be retained by Firefox from then on.

New Profile:

If the above fails to produce results, create a new Profile. This can seem a bit daunting if it hasn't been done before but isn't too bad if taken step by step. There is no need to delete/remove the current Firefox Profile in order to try a new one. An additional Profile can be created for test purposes. If Firefox runs OK while using the new Profile, it is probably best to think in terms of keeping it. Here are some steps that will necessary in order to do that:

a)

Build the new Profile up to requirements by reinstalling extensions/themes and customising the toolbars.

b)

A backup of the bookmarks file 'Bookmarks.(date) json', located inside the original Profiles folder, can be used to import bookmarks into the new Profile using the Bookmarks Manager (go to: 'Bookmarks > Organise Bookmarks > Import and Backup > Restore > Choose File ').

c)

Once the new Profile is set up and being used permanently, the old one can be deleted if desired by using the 'Profile Manager' (the link above shows the Profile Manager).

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. Once 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. There is perhaps some merit in creating a new Profile whenever a major upgrade of Firefox is released. This may help to keep Firefox running as smoothly as possible.

More information:

*

If the default Profile is deleted using the Profile Manager (see the 'Creating a new Profile' link above) Firefox will automatically create a new one when it starts. It would then be necessary to reinstall and set up: Bookmarks - Passwords - Themes - Extensions - Customisations. Although doing this may be considered a bother, it will often cure anything that is wrong with Firefox.

*

Before working with the Firefox Profiles Folder, make a copy of the bookmarks and keep it somewhere safe.

Firefox 3.0, bookmarks are stored in a file called 'places.sqlite', not 'Bookmarks.html' as with previous versions of Firefox. 'Places.sqlite' contains not only bookmarks but also browsing history. The 'Backup' option can be chosen to keep a copy of bookmarks and history instead of using the 'Export HTML' option. Both options are found in 'Bookmarks > Organise Bookmarks'.

The 'Backup' option produces a backup file called 'bookmarks(date).json'. This can be used for importing bookmarks and history into a new Firefox 3.0 Profile. The 'Export HTML' option can be used if preferred. This will produce a 'bookmarks.html' file. This can also be used for importing bookmarks into a new Profile. Bookmarks in this file will be imported into 'places.sqlite', whereupon Firefox 3.0 has no further use for 'Bookmarks.html'.

-----------------------------------------------------

*

The default location of the Profiles folder in XP is:
C:\Documents and Settings\YourUserName\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default

The default location of the Cache folder in XP is:
C:\Documents and Settings\YourUserName\Local Settings\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default\Cache

('xxxxxxxx' represents a string of random letters and numbers).
-----------------------------------------------------

*

The default location of the Profiles folder in Vista and Windows 7 is:
C:\Users\YourUserName\AppData\Roaming\Mozilla\Firefox\Profiles\xxxxxxxx.default

The default location of the Cache folder in Vista and Windows 7 is:
C:\Users\YourUserName\AppData\Local\Mozilla\Firefox\Profiles\xxxxxxxx.default\Cache

('xxxxxxxx' represents a string of random letters and numbers).
-----------------------------------------------------

*

The default location of the Application folder in XP, Vista and Windows 7 is:
C:\Program Files\Mozilla Firefox
-----------------------------------------------------

In conclusion:

The contents here aren't comprehensive. The real centres of help and information are the MozillaZine Knowledge Base and the MozillaZine forums. Nonetheless, perhaps this page gives an idea of what the Firefox Profiles folder does, why it is important and how faults might originate from it.