You'd need to explain what you did and what went wrong in the first place.

As indicated, when reinstalling thunderbird, I clicked an option (which no longer appears when I try again to uninstall and re-install) to allow Tbird to sync with google.

What appreas in Tbird now is the folder strcuture from my webmail (gmail). I want the old Tbird folder structure and the folder contents back. Those folders still exist in the profile.ini but Tbird is not directing there. I checked the ini text folder and it supposedly does point to the old profile - something is allowing Gmail folder structure to take precedence, and I can't find a disable or an account settings or any other way of disabling this and setting it back to populate from the Tbird profile.

when reinstalling thunderbird

Why did you reinstall Thunderbird?

I clicked an option

What option?

I want the old Tbird folder structure

How does the 'old Tbird folder structure' look like? Are you refering to folders as mail folders inside Thunderbird or a profile folder in the file system?

Those folders still exist in the profile.ini but Tbird is not directing there.

You can choose to start Thunderbird with a certain profile using profile manager. http://kb.mozillazine.org/Profile_manager

Not sure it's relevant, but I reinstalled Tbird because I had a problem with windows 10 that necessitated a re-set, and subsequently a reinstall of downloaded apps.

As I mentioned originally, I can't be specific about the "option" I clicked because I can't reproduce the problem. I only know Tbird asked me if I wanted to use my gmail credentials, or something, and I agreed to it, and the rest is current history.

As mentioned previously, the 'old Tbird folder structure' were folders as mail folders inside Thunderbird, but they no longer show up in Tbird. Tbird has replaced those folders with the ones from my online gmail account.

Those folders contained hundreds of emails I did not want to lose.

Not sure it's relevant

It certainly is. We just went from 'I reinstalled Tbird' to 'I lost my entire profile'.

Based on the (still) limited information I guess this is what happened: You reset your Windows installation, and with it went the Thunderbird profile. Most likely you didn't bother to create a backup of your Thunderbird profile prior to this. Upon reinstalling Thunderbird it didn't find an existing profile, so it did prompt you to create an account. You did and opted for IMAP, so you now see all your folders on the server.

You probably did use POP before, i.e. all your previously existing folder structure in the old profile was local.

Does this sum it up properly?

No; that's not it. In fact, as I have described the backup profile several times since my original question, I don't think your description of"not bothering" is fair.

I wondered about trying to switch to POP from IMAP but can't find that in Tbird. However I did find a file pathway for mail in one of the options tabs and was going to try entering the pathway to the backup manually to see if that would work.

So far your advice, if you can call it that, is mostly just condescending.

I have described the backup profile several times since my original question,

I don't think you mentioned the term backup prior to your last post. When talking about backing up the profile, this is what I mean. http://kb.mozillazine.org/Thunderbird_:_FAQs_:_Backing_Up_and_Restoring If you haven't created one yet, this may be a good time to do so.

So far your advice, if you can call it that, is mostly just condescending.

It is not my intention to sound condescending, apologies if I did. The thing is, I haven't given any advice yet, I'm still trying to understand your problem. It isn't really clear from your description, so I'll have to guess again. And using a little more accurate terminology would certainly help.

I did find a file pathway for mail in one of the options tabs and was going to try entering the pathway to the backup manually to see if that would work.

Can 'options tabs' be 'translated' to Account Settings - Server Settings?

Can 'a file pathway for mail in one of the options tabs' be 'translated' to the 'Local directory' setting within 'Server Settings'?

If so, leave it alone. Changing this will make things possibly worse.

Can you post the contents of your profiles.ini file?