I have Thunderbird and have restored it and my mail a number of times with no problems. I don't bother trying to save my settings; it's just not all that complex a program to set up! I simply back up the folder containing my mail. This can be found in C:\Users\Owner\AppData\Roaming\Thunderbird\Profiles where "Owner" is your user name.
If you look in that Profiles folder you'll find a folder with some strange code name. Mine's currently "sp6tht5i.default". Each time I've installed it's been different so I'm not sure what determines it! Assuming that you're the only one using it there will only be one folder. It contains all your settings plus your mail, so basically I would assume that if you back this up you'll be fine. As I said, however, I don't bother doing this - I just backup the one folder inside it called "Mail". Well... actually, if you look inside it you'll find that it contains multiple mail folders. At a minimum it will have ones called smart mailboxes, Local Folders and whatever your accounts are. Whether you want to backup all of them depends on what you use. Personally, although I have more than one account that is read by Thunderbird, I have things set up so that they all dump into the one main one. So again, that's all I bother backing up!
When I've been feeling paranoid and wanted to be sure I had my settings backed up I've occasionally gone to the Account Settings screens in Thunderbird and done a succession of Alt+PrntScrns to capture the images of the settings, pasting them into Word and saving this. I've never needed this though.
Basically the procedure for restoring is:
1. Install Thunderbird.
2. Set up your account as per usual. Send yourself a test mail to ensure it works.
3. Exit Thunderbird.
4. Locate your Profile's folder again and replace the Mail folder with your old one. I assume you might also here replace the settings files but I've not done that, only the Mail folder.
5. Load Thunderbird again.
Easy.
I'm sure that someone else will now proceed to tell me all sorts of easier ways to do this but it's worked successfully for me now for 10 years, starting with the old Mozilla program that Thunderbird replaced (name escapes me now).
Note that all of this is assuming that you store your mail on your local machine. ie that you don't have one of the accounts (IMAP?) where the mail is stored remotely so that you can access it on multiple machines. I've never wanted to do that so I always set up my accounts as POP3 style and all mails are downloaded to the local machine immediately and stored only there.
