Hotlinks from Thunderbird emails do not open in Avast secure browser

[trinchen]

I have had Avast secure Browser installed for years and it has worked perfectly. For a few weeks now the links in emails arriving in Mozilla Thunderbird (update 2/7/20, 68.10.0 (20200629235513)) are not opening in Avast Secure Browser (83.0.4530.98) automatically. Instead an error message pops up to say "this file does not have a program associated with it." The Avast secure browser is set as as my default program.
Copying the link manually and pasting it into the Avast browser opens the correct web page. 
If I change my default browser to Chrome, the links from the emails work. Changing it back to Avast Browser recreates the problem.

Is there an incompatibility with the Avast Browser which started in the last few weeks?

Starting Thunderbird in safe mode (without add ons) does not rectify the problem.

Any suggestions how I could get the link to the Avast program working again?

[DavidR]

What browse it open or go directly to when you click al link ?

What if you right click on the link and select the Open link in browser and see if that gives you an option as to which browser to use ?

I use Thunderbird and that opens with my default browser Firefox.

Edit: I just did a test setting ASB as my default browser and Thunderbird opened the link in ASB, so it is working for me.

[trinchen]

Thanks for your reply DavidR. Right click, open in browser does not work either.

Why does Thunderbird not recognise the Avast secure browser as default browser now, when it did before???  Thunderbird recognises other browsers when they are selected as default program!!

I would appreciate some help.

[DavidR]

As I said it is working as expected for me as I tested after my post and added the EDIT: and images.

You could try an Avast Repair - Avast UI > Menu > Settings > General > Troubleshooting - Repair App.
Reboot after the Repair.

[trinchen]

Thanks.
The repair (and reboot) suggestion did not solve the problem. 
I also reset the browser to the default settings. No luck.
I tried to uninstall the browser (browser only, not the antivirus program) but for some reason get told that I don't have administrator rights ...even though I am logged in as administrator...??!!

[DavidR]

Thanks.
The repair (and reboot) suggestion did not solve the problem. 
I also reset the browser to the default settings. No luck.
I tried to uninstall the browser (browser only, not the antivirus program) but for some reason get told that I don't have administrator rights ...even though I am logged in as administrator...??!!

Having Administrator sights on your user account (same as mine), is still different. 

Whilst the Avast Secure Browser (ASB) is a stand alone product, when installed and avast antivirus is also installed there is some integration (to give greater protection to ASB).  So I don't know if that has any impact (Avast Self-defence module) on what you experienced.

[trinchen]

It is still not working and I have no solution yet. Can any of the programmers find out if it is related to the last update?

Thanks

[DavidR]

Check this out and see if the Avast Secure Browser is set as the default browser in Thunderbird for internet links.

https://www.lifewire.com/change-the-default-browser-in-thunderbird-2532751

The Problem

Thunderbird doesn't operate alone. When you install Thunderbird on your computer, you're installing it with a number of other applications. Some of these applications may get called into action based on the contents of your emails. In the case of the uniform resource locators (URLs) you click, like website addresses, Thunderbird usually passes the event off to your default web browser.

Under normal circumstances, this all goes off without a hitch. Most operating systems give you the option to choose a default web browser in some configuration screen, and most web browsers give you a way to choose them as your default option. Sometimes, however, things go wrong, and you need to know how to tell Thunderbird explicitly which web browser you want it to use.

The highlighting is mine, so follow on from that paragraph and see how to set it manually for your browser of choice.

EDIT: this is old so you need to start using the 3 bars Menu icon then go to Advanced, Config Editor... button at the bottom.  Now you should be able to continue from Step 6. of that instruction.

[rocksteady]

...
I tried to uninstall the browser (browser only, not the antivirus program) but for some reason get told that I don't have administrator rights ...even though I am logged in as administrator...??!!

If you still wish to uninstall ASB, you could also try the ASB uninstaller app which can be downloaded from Avast. See here:
https://support.avast.com/en-us/article/Uninstall-Secure-Browser#idt_030

[trinchen]

I re-installed Avast Browser and reinstalled an older version of Thunderbird (as it was working till June and there had been an update of Thunderbird in July) but the problem persists even with the older version of Thunderbird. The link to the internet does not work if the default browser is Avast secure browser, but it works when Chrome is the default browser. So I conclude there must be some incompatibility between Thunderbird email client and the Avast secure browser.
Any other thoughts from the programmers?