There have been no changes to filters that I am aware of. Mine all work. But I do not have an antivirus scanning changed files in my profile folder either. Do you?

Thank you for your reply, but I really don't know if I have an "...antivirus scanning changed files in my profile folder..." or not! I don't know anything about "profile" folders. I didn't tell my antivirus to do anything with TB. All I want to do is to be able to read my emails and have some of them moved to special folders like they once were handled. I'm 84 years old and don't care about fancy colored folders and all of the other "pretty stuff"! Just give me a reader that I can use to read my email and do a few simple things to make life more simple. Thanks again.

Maybe, if you post a screenshot of a filter you have, someone here can assist you. Thank you.

Thank you David for your reply; however, I have absolutely no idea where to find the filters now. My filters haven't worked since when everything was royally screwed up with that first major change (version 90 something) was made to TB a long time (a couple of years, maybe) when I lost everything folders, emails, address book, etc. I have never fully never fully recovered from that fiasco. I have limped along using TB for nothing but basic reading and sending emails. I have only recently tried to create a filter to collect the emails from a daily news source. I don't even know where to start with all this profile stuff. I am not a Geek! I am just an 80+ year old man trying to survive in this modern world. Thanks again for replying to my inquiry.

Filters are still the same, so I encourage you to play around with them. Select Tools>message filters and you will see the same pane you saw in the past. Also, I encourage you to periodically do a backup of your profile. The simple way is to install the import/export addon and select tools>importexporttools NG>export profile>fullprofile. Then, should you have have an update that has problems, you can restore from the backup by clicking Tools>import>import from another installation.

I've had it! Now when I went to get an address, my Address Book is gone!!!!! All of my contacts over the past x number of years are gone. Is it anywhere to be recovered from? HELP

How long since you used your addressbook? Days or months? Did you recently do an upgrade of THunderbird? When you click the 'write' button and then press F9, does a list of addresses show on the left side? If nothing, you might click help>troubleshootinginformation, scroll down to 'profiles' and click 'about:profiles' and that next pane should show a list of known profiles. With that info, you could check to see if one of them has your abook.sqlite file, which is the addressbook. If one profile has a bigger addressbook, that may be it, and you could copy it into your active profile.

So far, so good. However; what is my "active profile" and where is it?

click help>troubleshootinginformation, scroll down to 'profile folder', click 'open folder' and you will be in the profile, viewing from windows file explorer. Note the folder name for future reference.