Here is a way to let thunderbird update profiles.ini for you. These steps are because you COPYed the profile to D, meaing it is now in both places.

1. click help>troubleshootinginformation
2. scroll down to 'profiles' and click 'about:profiles'
3. click the 'create profile' button
4. click next
5. enter a shorthand name for profile, such as, PROFILED
6. now, click the 'choose' button and locate and select the profile on D
7. now, select finish and launch
8. after confirming that all is well, you can safely delete the profile on drive C.

IF you no longer have a profile on C, then do this:

1. click windows key and 'r' key on desktop
2. enter thunderbird.exe -p in the window
3. click the 'create' button and proceed as above.

Thank you David

I actually MOVED it to D:\Thunderbird\Profiles Then I copied it back to C:\ haha

Anyway, I tried what you said and clicked "launch profile in a new window" but it doesn't load. It asks me to setup an existing email. If I do that, it creates a new profile again (see screenshot attached)

I see now three different profiles. The only correct one should be the one on D:\Thunderbird\Profiles

Thanks in advance for your help.

you did not follow instructions. step 6 was to locate and select the profile on D. Since you had copied from C, it should have retained the same name. Carefully do it again. I just went through the steps myself and it works perfectly.

You're correct. Sorry. I don't know what / how I did step 6 the first time. It works now. I opened and found out I have a bunch of INBOX-1 / INBOX-2 etc.. (see screenshot), do you know why and if it's safe to delete ?

Also, how can I set this profile on D as default profile ?

Thanks Phil

Screenshot forgotten. Here it goes

EDIT : Closed Thunderbird and reopened. Those -1 -2 folders disappeared.

Problem solved. Deleted all other profiles safely.

Thanks a lot for your help.

Is this an IMAP account? If so, you can exit thunderbird and delete all of them and restart thunderbird. If that makes you nervous, copy them somewhere first. When you restart thunderbird, isn't that already the default?

Don't delete everything, just those with the-1,-2 ,entries, such as inbox, inbox-1, inbox-2, etc. all msf files can be deleted. I would leave all others alone

It's not IMAP, nope. Those all disappeared on their own. Everything is back to normal and yes, when I launch Thunderbird, it's directly the D profile loading. It's all working out perfectly, thanks a lot for your help !