A simple way is to create two profiles, as that gives each of you full use of Thunderbird, yet fully separate from the other's profile. Then, set up two shortcuts on desktop (I am assuming Windows), with each shortcut pointing to a different profile. It's one version of Windows, but two profiles.

This is only half the problem solved. I can (have) created many profiles. Exactly what are the steps to go from one profile to another:

   How to log out of first profile on Kubuntu.
   How to login to other profile other profile.
   What's in the shortcuts?

Thank you,

John Latham

The shortcut must have these parameters -p profile-path. For example, in Windows, it may look like this:

 thunderbird.exe  -p   c:\profilefoldername      Then, if you can have two shortcuts on desktop, just close one copy of Thunderbird when done and click the other shortcut to start the other. I wish I could be more specific  for Linux.