From MozillaZine Knowledge Base

This article explains how you can start with a specific profile when you have multiple profiles for your Mozilla application.

Profiles listed in the Profile Manager

When multiple profiles are listed in the Profile Manager, the last selected profile is automatically used, unless you uncheck the "Don't ask at startup" option. If you don't wish to always see the Profile Manager at startup, you can use the -P "<profile name>" command line argument, either directly or from a desktop shortcut, to start your Mozilla application with a specific profile. See Shortcut to a specific profile for details.

Bypassing the Profile Manager

The following does not apply to Mozilla Suite/SeaMonkey 1.x.

You can use the -profile "<path>" command line argument to start Firefox, Thunderbird, or SeaMonkey 2 with any specified profile, whether or not the profile is listed in the Profile Manager. This can be useful when recovering a profile that is missing from the Profile Manager, which could happen if the profiles.ini file was deleted or incorrectly edited. You can also try out a profile you've copied to a new location or test a profile backup before adding it to the Profile Manager in this way (see Moving your profile folder for details on that process).

Desktop shortcut

On Windows

Create a new Windows desktop shortcut to your Mozilla application (or copy an existing shortcut). Using Firefox as an example, right-click and rename the new shortcut "Firefox MyProfile" , then right-click the shortcut again and select "Properties", go to the "Shortcut" tab, add a space to the end of the path in the "Target" box, then add -profile, another space, followed by the path to the profile folder enclosed in quotes. Using a custom profile folder path of D:\Firefox\Profiles\MyProfile as an example, the Target box will show:

"C:\Program Files\Mozilla Firefox\firefox.exe" -profile "D:\Firefox\Profiles\MyProfile"

Command line

On Windows

You can use -profile "<path>" from the Windows "Run" dialog box to start a specified profile. Using a Firefox profile folder, C:\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\xxx.default as an example (where <user> represents your Windows log-in user account name):
Click the Windows "Start" button, select "Run", type the following in the "Open:" field, then click 'OK"

firefox.exe -profile "C:\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\xxx.default"

Creating a profile that is not listed in the Profile Manager

You can use -profile "<path>" to create a new "unlisted" profile at a given location, without starting the Profile Manager. This can be useful for troubleshooting. You would first create a new "empty" folder for the new profile. You would then use a desktop shortcut or the command line, as explained above, to specify the path to the newly-created folder. The profile data for the new profile will be stored in that folder but the profile will not be listed in the Profile Manager or in the profiles.ini file.

See also

• Command line arguments
• Command line arguments - Thunderbird