The aim of this page is to document all the information on Mozilla Profiles that I have.
There is, of course, a lot of common ground between Firefox and Thunderbird, especially around profiles, so let's deal with the common stuff. To see what is going on with profiles the "easy" way to get profile information is via the "hamburger" menu, from where you can select Help and then "Troubleshooting Information", this opens a page where you can click "about:profiles".
The about:profiles page will give you all the profile information you need. Typically it will show you a single, default profile that has two directories, a "Root Directory" and a "Local Directory", these will both be located in an area of your drive that is for user specific information, whether on Mac or PC. Here you can create new profiles, and these will also have two directories. However, if when creating your profile, you choose another directory, say on Windows that might be "D:\Mozilla\Firefox\MyProfile", then you will find that single directory, labelled "Root Directory", is in fact the other two merged together.
When I wanted to save space on my C drive, I decided to move my Firefox profile to my D drive, this is what I did:
There are a good number of useful pages on this subject, here are some:
Many is the occasion where I have moved a profile from one computer to another. The steps are as follows:
If you simply want to move the profile from one location to another, to make backup easier for example, then take a look at Moving your profile folder - Thunderbird - MozillaZine Knowledge Base. I have done this myself and chose the modifying the profile.ini file technique, which worked fine.