Starting the Profile Manager

Profile Manager is not displayed by default. Instead, you must start Thunderbird with a “switch” that makes the Profile Manager appear:

• Press +R on the keyboard to open the Run dialog. Then enter “thunderbird.exe -p” and click OK.

Note: If the Profile Manager window does not appear, you may need to specify the full path of the Thunderbird program, enclosed in quotes; for example:

On 32-bit Windows: "C:\Program Files\Mozilla Thunderbird\thunderbird.exe" -p On 64-bit Windows: "C:\Program Files (x86)\Mozilla Thunderbird\thunderbird.exe" -p

If the Profile Manager window does not open, Thunderbird may have been running in the background, even though it was not visible. Close all instances of Thunderbird or restart the computer and then try again.

Creating a profile

To create a new profile, click the Create Profile… button. After specifying a name for the profile, you may also specify a custom location for the profile folder (or click Finish to use the default location).

Renaming a profile

To rename a profile, highlight the profile in the Choose User Profile window and select Rename Profile…. Give the profile a new name and click OK.

Deleting a profile

To delete a profile, highlight the profile in the Choose User Profile window and select Delete Profile…. Click Don’t Delete Files if you only want to remove the profile from a list but keep its files. Click Delete Files to permanently delete the profile and all its data.

Note that you cannot delete a profile by simply deleting the profile folder from the disk. It will still be displayed in the list of available profiles.

Options

Work Offline

Choosing this option loads the selected profile and starts Thunderbird without connecting to the Internet. You can view messages saved to your computer and experiment with your profile.

Use the selected profile without asking at startup

When you have multiple profiles, this option tells Thunderbird what to do at startup:

• If you check this option, Thunderbird will automatically load the selected profile at startup. To access other profiles, you must start the Profile Manager first.
• If you uncheck this option, Thunderbird will show you the Profile Manager each time you start it, so that you can select a profile to use.

Credit : https://support.mozilla.org/en-US/kb/using-multiple-profiles#w_creating-a-profile