Do you use CCleaner or similar? If so, tell it to ignore Thunderbird's profile folder.

I only have my antivrus program and I do not want all my emails to be unprotected. Viruses are often sent via emails.

I asked specifically about CCleaner because it removes session files that store Thunderbird's state and configuration. Settings that don't stick are often caused by loss of the session files.

Do you allow Thunderbird to add these senders to its Address Book? The Address Book is used as a whitelist. I set up a specific address book just for commercial vendors and the like just to permit their images. They don't need to clutter up your working address book(s).

That is another issue. I too put commercial emails into a separate folder. But when I enter them manually they disappear for some reason. ie: I make out a new contact for a phishing email address from my bank. When I try to bring that info up to add it to a suspicious email that I am forwarding to my bank, the info/contact has disappeared. Is their a specific folder/file that I can tell my antivirus to ignore to prevent this?

Here is the nub of the problem, I think. You need to store the sender and if it can't be added to your Address Book, Thunderbird can't remember that you wish to see remote content.

An address book that won't store changes may have a corrupt data file. Export each affected address book to an LDIF file, close Thunderbird, delete the corresponding mab files from the profile, re-start Thunderbird and re-import from your mab files.

I don't seem to have the option of exporting to a LDIF file and when I try to create a new contact list the new contact goes to one of the already created contact lists. This should not be this hard. Thanks for your help but I am going to look for a simpler email client.

You select the type of file to export to. It defaults to LDIF. Getting folk to use CSV is the more usual problem, along with explaining that they are being asked where to put the exported data and not to choose from where it comes.

I don’t know of anything called a Contact List. You have Mailing Lists and address books. Unless you can be more precise, I'd have to guess at what you mean. At the moment, I think your Address Book is broken and I don't know of any way to fix it other than to export and re-import. Sorry.

http://chrisramsden.vfast.co.uk/11_Thunderbird_Settings_and_the_Profile.html.

When you right click on an address book it gives you an option of creating a "New Contact" hence my using that term. My original issue has been an issue since I started using T-Bird. I thought that an update may fix it. And I have reinstalled a completely new T-Bird taking care to clean my system of anything T-Bird related including registry items. Like I said, it should not be this hard. Thanks for your help.

Thunderbird doesn't use the Windows registry. For a clean start you'd need to use a new profile, and one way to do that is to delete, rename or move your existing profile.

http://kb.mozillazine.org/Profile_folder_-_Thunderbird