If the retail program is 32-bit, you should revert to Thunderbird 32-bit.

So I just did that and now I cannot connect to my original profile which apparently has been moified by the 64 bit Thunderbird. I will lose everything that was in the old profile. Messages, addresses, stored emails, everything. Is there any way to get it back?

In fact, I no longer even have the email address that gets these messages.

Is there any way to get it back?

Reverting to 64-bit should load your profile just fine.

Is there any way to get my old address books back. I had a tremendous number of collected addresses that I use regularly.

If I revert to 64 bit, Thunderbird will not work with my retail program. The original advice was to switch back to 32 bit. It worked but I lost everything.

Restoring the addressbooks is a simple matter of copy-paste. See https://support.mozilla.org/en-US/questions/1348901

You can use the Profile Manager to load your old profile. See Profiles - Where Thunderbird stores your messages and other user data

Profile Manager - Create and remove Thunderbird profiles

Unable to use profile when you launch an older version of Thunderbird

Dedicated profile per Thunderbird installation

I did that. Still missing hundreds of addresses and search doesn't work.

Now the address books have the message "This address book shows contacts after a search but it doesn't allow a search.

Also, I no longer can edit details of an email address that I select from an incoming email.

Nearly all address book functionality is gone and most of the addresses.

Install 64-bit in a separate location, then make a copy of your profile folder and launch the 64-bit version using that copy. See if it loads your address books.

I am not sure how to do that. I cannot save addresses at all. There is no search capacity. The address book is not functioning and I lost a couple thousand addresses.I am pretty sure I properly identified the address info in the old 64 bit profile and copied it into the new profile. it is like the main address book list is missing. Only collected groups appear.

Also, when I click on an email address from a received email, I cannot edit it. The only button that works is the "Delete" button.

I am not sure how to do that.

See the links I posted earlier.

Appreciate the help but for my use, this is too complicated.

Is there a reason the new profile will not let me save or edit new email addresses?

Is there a reason the new profile will not let me save or edit new email addresses?

I honestly don't know, because a fresh new profile should not have such flaws, unless you copied the troublesome abook file to the new profile's folder.

I really appreciate your help. Is there a way to install a second Thunderbird in 64 bit, connect it to the 64 bit profile I still have and use the 32 bit just for the retail program it interfaces with?