See Profiles - Where Thunderbird stores your messages and other user data

You can also move your entire profile folder to a different drive, create a new profile and configure it to use the relocated profile folder. Just make sure you exit Thunderbird before copying or moving the profile folder. Also, make a backup copy of the profile folder just in case, and make a habit of backing it up regularly if you treasure your messages.

Many thanks Stans - it looks like I'll need to edit my profiles.ini file. However, currently it contains a path variable like so:-

Path=Profiles/bvjnaw0d.default

which is a folder on my C: drive. Let's assume I copy that whole folder to D: somewhere... do I still need it to be in a folder called Profiles? Or can I just change that entry to something like this:-

Path=D:/some root folder/bvjnaw0d.default

Also... is the root folder path allowed to contain spaces?

I never bothered with editing the profile.ini file before, so I can't give you a precise answer about that. I've always used the profile manager and let it take care of maintaining the profile.ini file for me. Launching the profile manager is as simple as running

thunderbird -p

from the Run utility in Windows, which you access by pressing the Windows and R keys together.

I took your advice Stans and used the profile manager, rather than trying to edit stuff manually. After backing everything up I created a new profile for my other hard drive and then copied all the relevant files+folders to it. I then deleted my original profile and set it to use the newer one. And bingo! It all seems to be working!! I haven't tried sending an email yet but it seems to be receiving okay and it's using the newer drive and profile. Thanks for all your help with this.

The only confusing thing is that the top of the old profile looked like this:-

    [Install8216C80C92C4E828]

    Default=Profiles/bvjnaw0d.default

whereas the new one seems to have an extra line:-

    [Install8216C80C92C4E828]
    Default=F:\Thunderbird\Profiles\tw32lt9u.f-drive
    Locked=1

I'm just wondering what Locked=1 means??

Sorry if this comes through twice (this morning's post didn't show up the first time...)

I took your advice Stans and used the profile manager, rather than trying to edit stuff manually. After backing everything up I created a new profile for my other hard drive and then copied all the relevant files+folders to it. I then deleted my original profile and set it to use the newer one. And bingo! It all seems to be working!! I haven't tried sending an email yet but it seems to be receiving okay and it's using the newer drive and profile. Thanks for all your help with this.

The only confusing thing is that the top of the old profile looked like this:-

    [Install8216C80C92C4E828]

    Default=Profiles/bvjnaw0d.default

whereas the new one seems to have an extra line:-

    [Install8216C80C92C4E828]
    Default=F:\Thunderbird\Profiles\tw32lt9u.f-drive
    Locked=1

I'm just wondering what Locked=1 means??

I strongly recommend you do not manually edit the profiles.ini file. Use only the profile manager of the About:profiles accessed from the troubleshooting information on the help menu.

Locked is a component value of the profile per install https://support.mozilla.org/en-US/kb/dedicated-profile-thunderbird-installation it is linked to the installs.ini file.

Thanks Matt - I followed your link and it sounds like the locked status is linked to Firefox somehow (I was just worried in case it'd maybe prevent me from making future changes...)

BTW... is it possible to choose one's own user name here? Most forums offer you that option when you first register - but here, it just seemed to choose a name for me  :-(

re :BTW... is it possible to choose one's own user name here?

Yes. When logged on to this forum to post comments, you will see your name top right.

• Hover over name and a drop down offers 'View Profile' - select it.
• In profile and on the right side it will offer 'Edit My Profile'.
• This offers you a place to create a 'Display Name'.
• then click on 'Update my profile'