The easiest way is to create a new profile, delete it's contents, the copy the entire contents from old profile to the new profile. Then select each profile and remove the accounts you do not want, so ending up with 3 on each (but not same three of course) How to create a new profile: In Thunderbird * Help > Troubleshooting Information * Under 'Application Basics' near the bottom - Profiles - click on 'about:profiles' It will open in a new tab * click on 'Create a new Profile' * Enter a new profile name in text box * click on 'Finish' It will appear in the list in the 'about:profiles' tab Profile: name of new profile * You will see 'Root directory: where it is stored and a 'Open Folder' button - click on it. It will open in a new window showing a load of default folders and files. * Now get the current default profile open in the same way. So you now have two new opened windows showing the contents of each of your profiles. * Exit Thunderbird now - this is important. * New profile - delete all the contents of that new profile, so 'profile name' folder is empty. Do not delete the actual 'profile name' folder itself. * Old profile - Copy all the files and folders - all contents. * New profile - paste in all the copied files and folders This now means you have two identical profiles using different 'profile name' folders. * Start Thunderbird and it will start as per usual on default old profile. * Access the 'about: profiles' tab again - it should still be open * look for the new profile * below it's data, it will say 'Launch profile' although some reports still say it says 'Launch profile in browser' - it does not launch in a browser - it opens another Thunderbird window, but a differnt profile. click on that 'Launch...' button Now you have two Thunderbird running. You can remove accounts, so only keeping the ones you need. * Right click on mail account name in Folder Pane and select 'Settings * Select the account name you want to remove * click on 'Account Actions * click on 'Remove account' * Repeat for any other account you want to remove. Then access the other Thunderbird that is running and perform the same actions, except make sure you do not delete the same accounts as previously, so keeping different mail accounts on different profiles. This method is so much quicker than you think.