Thunderbird became corrupted,

Please explain what that means. It would be very unusual if the application itself became 'corrupted'. Typically the problem is within the your Thunderbird profile. In that case reinstalling the application is a waste of time.

had to download and install again. But Thunderbird has not picked up any of old mail files.

Downloading and installing Thunderbird does nothing to an existing profile. Presumably you also did something else you haven't mentioned yet.

I dont want to lose, had not saved these to my H/drive

Whatever your 'H/drive' is, if you're concerned about data loss create a full backup of your Thunderbird profile. https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile

I have found them all in "Thunderbird → Profiles"

Please provide the full path including the name of the profile folder.

How can I reinstall

Didn't you do that already?

Hi, Yea, Thunderbird/ computer ???? was getting worse by the day, it just would not connect to the internet I had to start the computer, then hold the power on and go into safe mode, often twice B4 it would connect, Couple days ago I downloaded Thunderbird again, but would not pick any of my old stuff, asked, had to, fill it all setup info again. Looks like i found the files here (below) but not registering with this new installation If I go to folder "Mail" looks like all my headings are there and fair amount of data AppData\Roaming\Thunderbird\Profiles\gfwhrxwb.default\Mail\Local Folders Thanks Cheers

AppData\Roaming\Thunderbird\Profiles\gfwhrxwb.default\Mail\Local Folders

The full path starts with a drive letter. As requested before, please provide the full path,

In addition, what is your current profile folder? Please provide the full path. https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data

Also, please post the contents of your profiles.ini file. It's located at C:\Users\<user_id>\AppData\Roaming\Thunderbird.

I do thank you, and did not desert, was, am, busy with Stuff that required urgent attention, as well as my lost Emails. Full address is C:\Users\RJbiz\AppData\Roaming\Thunderbird\Profiles\gfwhrxwb.default\Mail\ which goes to two folders

Local Folders

Local Folders-1 Both appear to have my files Thanks

Local Folders Local Folders-1 Both appear to have my files

What does this mean? I'd expect 'Local Folders-1' has a more recent time stamp than 'Local Folders' and so would have any files underneath. Is the contents the same in 'Local Folders' and 'Local Folders-1'?

I wouldn't expect is it. Does 'Local Folders' have the missing messages? You can open mail files (those without a file extension) with a decent text editor.