This is usually a Windows problem. Have you checked to see what the default app is for html? That has often been the issue.

HTML Links work in other applications, but not in Thunderbird. How do I check to see if Thunderbird uses Chrome as it's default app?

In troubleshooting, I think it's important to first verify with Windows what is the actual default browser. The Default Apps app will identify that.

According to windows Default Apps settings, Google Chrome is set as my default browser, so that does not appear to solve the problem. I do appreciate you trying to help me with this. I've been trying to get support on this problem for over 3 months now.

See if this helps: https://www.lifewire.com/change-the-default-browser-in-thunderbird-2532751

Now, I'm really lost! I copied and pasted that link in Chrome. the first line: Go to Menu - Preferences - Config Editor. There is no reference to MENU on my Thunderbird opening page While looking for it, I may have messed up other things. Sorry, but I have to ask what am I doing wrong? These links used to work in Thunderbird, then they just quit.

Would re-installing Thunderbird put things back the way they should be? If so, how do I protect my address book and emails that are stored in various folders?

Seems what I really need is a remote connection with someone like you who knows his way around this program. Is that type of service available? I know that I use Team Viewer to link up with friend's computers to help them with family history.

Sorry, the substance is correct, but the Thunderbird menus have updated. You want settings>general to get to config editor. The 'preferences' was replaced with 'settings' a couple of updates back. From settings>general scroll down to bottom right for config editor.

David, the more I try to fix this, the more new problems appear. Last night I tried to send email to a friend and the SEND option had changed to SEND LATER. That mail is still in my DRAFTS folder and I'm unable to send it or any other mail.

    Is it possible to start from scratch by removing and reinstalling Thunderbird?
    My only concerns are: what happens to my Address Book and all of the email I have saved in organized folders?
    I've uploaded the Thunderbird menu bar screen view so you can see what I'm looking at.

- Jim Archibald

That is usually indication of being offline. CHeck File>offline and see if 'work offline' is ticked.

I checked File>Offline and it is NOT checked. The HELP button in the menu does nothing, and F1 is the same, so I can't get any help from within the program. Thunderbird just updated to 115.5.1 I'm afraid the time has come for me to find another email program. These problems with Thunderbird and just getting to hard to solve. It worked so well for me for many years, then the links stopped working and that just led to more and more problems. David, I do want to thank you for trying to help me with this, but clearly nothing is working and the more I try, the worse it gets. Do you have any suggestions for an good email program other than Thunderbird?

Before doing anything drastic, did you follow the config entry change? That's important and, if it works, will save you much trouble in going elsewhere. Thunderbird has this active support forum and you will not find one elsewhere with another client. Let's work through this.

network.protocol-handler.warn-external.http & https were both set to true.

When I tried to open a link with a URL ....nothing. See the image below that shows what I have to do to open those links.

Right Click on "Learn More" - select "copy link location" - manually open Chrome browser - paste and go to https://support.mozilla.org/en-US/questions/1432317?utm_campaign=questions-reply&utm_source=notification&utm_medium=email#answer-1621168

That's the only way I can use any links in Thunderbird mail.

One more step that I forgot: click settings>general and scroll down to files&attachments. You should now see an entry for https. Click that and set to preferred browser. Let me know how it goes.

No, that's not the problem. I've attached screen shots of those settings and they appear to be right.

There appear to be some duplicates there. You might try changing default from Chrome to 'just ask' to see if you get prompted for a browser. I'm just guessing here, but those duplicates are puzzling.

Tried that with no improvement.

However, I did notice in the Server Settings it is showing an email address I very seldom use -jimarch36@gmail.com. I always use jimarch@shaw.ca.

Could that be the problem and should I change it?

I am at a loss. and will attempt to locate someone with more expertise on this. Frustrating.

Thanks for hanging in there with me, David. A few others have tried and just gave up. Tell me, if I were totally uninstall Thunderbird, then re-install the latest version, could that get us out of this? Of course I would first need to know how to back up all my data ....saved email, address book, etc. What do you think, could that work? The reason I ask is because for years Thunderbird worked for me. I must have done something a while back that caused this problem.

That's an option. your addressbook is abook.sqlite and can be safely copied elsewhere to be reinserted after a new installation. Same for any POP messages or Local folders folders. Those are in the Mail folder in profile and can be copied out with WIndows File Explorer to later be reinserted. Any IMAP folders will be repopulated automatically. If you have POP folders, let me know and I'll give more specifics.

Sorry David, but I can't find abook.sqlite, the address book. I can't I find it anywhere in C:\Program Files\Mozilla Thunderbird\*.* Am I looking in the wrong place? I may need a bit more detailed info on the backup process. I should mention that although I've had a computer (Apple 2+, Apple e) since 1980, then Microsoft since then, I have reached the ripe old age of 87 and see to be having trouble keeping up-to-date with all the changes in Technology. Running Windows 10 now on a desktop computer - Jim