Hi I have a setup with my machine where I use different user accounts for different purposes as this helps me manage a large number of different applications and setups. I want to use the same Thunderbird profile for each of these users as I am the same physical person, these are logical users not different people, and therefore the profiles will never be in use simultaneously. Research on the internet suggests that this can be done by copying the Thunderbird profile to a globally accesible directory and then using the Profile Manager to point profile.ini to the global profile. I have done this but when I try to launch Thunderbird from a different user I get a message box saying 'Thunderbird is already running, but it is not responding. The old Thunderbird process must be closed to open a new window.'. If I click on 'Close Thunderbird' the message reappears. I have confirmed in the Task Manager that the Thunderbird process is not running. Strangely, if I launch Thunderbird from the command line version of the Profile Manager Thunderbird launches with the correct profile and appears to work fine. A forum post suggested deleting the parent.lock file in the profile and doing this does allow Thunderbird to launch with the correct profile but then I get error messages saying it could not load the message summary as it's too big. I have looked at this link [http://kb.mozillazine.org/Moving_your_profile_folder_-_Thunderbird#Sharing_a_profile_with_another_user here] but it's not clear what is meant by 'have each user "move it" using the profile manager'. There is no move option in the Profile Manager (as launched from the command line), just Create Profile, Rename Profile (which I've tried as another user with the same problem suggested) and Delete Profile. Here is my current profile.ini for the users that won't launch Thunderbird. [Install8216C80C92C4E828] Default=C:\ProgramData\Thunderbird Locked=1 [Profile2] Name=MarkDevelopment IsRelative=0 Path=C:\ProgramData\Thunderbird [Profile1] Name=default IsRelative=1 Path=Profiles/uzxtlmbg.default Default=1 [Profile0] Name=default-release IsRelative=1 Path=Profiles/hcw0nqcr.default-release [General] StartWithLastProfile=1 Version=2 Any help would be greatly appreciated. I am using Thunderbird 115.2.0 (64-bit)