Latest PureOS update breaks Thunderbird apparmor config

As of 16 June PureOS update, Thunderbird no longer opens web links in Firefox (default browser). I executed:

/etc/init.d/apparmor stop
to verify that Tbird opens links in Firefox when apparmor is OFF.

I have fixed this in the past with a change to apparmor config but I can’t find any document I saved to document this fix and I can’t get past all the extraneous help answers to find one that documents the apparmor config change necessary to re-enable Tbird links.

I would appreciate a link or edit to fix this problem.

I’m running PureOS Amber and updated as well, current Thunderbird version is 68.9.0. Links properly open in Firefox… Sorry, this might not be of much help.

No, this is helpful. I have a confusing array of issues:

Running latest PureOS amber. No other repositories.
Tbird (68.9.0-64bit) keeps re-appearing “Blogs & News Feeds”
Ffox (77.0.1-64bit) keeps asking to set default browser

URLs don’t open in Tbird, complaining about “feed not verified”.

Disabling apparmor appears to solve problem of links.

All this seems quite inconsistent.

My setup is fairly similar. I have a few additional repos, but nothing that should conflict with Tbird and Ffox. Tbird is installed on my system via the standard pureos repo. How did you install Ffox? In my case I use the Linux binary that I got from the mozilla website (I saw there’s also a way of installing it via flatpak but I didn’t do that). Never had problems with Tbird, “Blogs and News Feeds” does not re-appear on mine… I do occasionaly get a pop up for Ffox that asks me to set is as the default browser. If I check the GNOME default applications menu it will still show that my version of Firefox is the default browser. But this pop-up has been really rare recently.

For my Ffox installation I created my own .desktop file for GNOME, have you done something similar?

This is a very long-shot, but can you verify the path for Firefox 77.0.1 in the apparmor profile? I think Amber uses firefox-esr. Long ago, there was a similar issue with PureBrowser, and the suggestion was made to add the correct path/permissions.

If you are like me and download Firefox from Mozilla, I suspect the path to Firefox might be different than the profile. (I do not allow links to open from Thunderbird, so I do not see the problem.)

I have installed Mozilla Firefox from the Mozilla binary. PureBrowser on my system has evolved to “Firefox ESR”. I have not had any conflicts between the two versions before now.
I have not created a .desktop file and do not know what I would use that for.

Perhaps my apparmor config now points to Firefox ESR and not Mozilla Firefox.

/etc/apparmor.d/local/usr.bin.thunderbird is:

/usr/lib/purebrowser/purebrowser mixr,
/opt/firefox/firefox mixr,

The firefox path is correct, but of course purebrowser no longer exists. /usr/lib/firefox-esr exists.

Interesting, /etc/apparmor.d/local/usr.bin.thunderbird is empty on my system…

.desktop files basically tell GNOME where to find binaries. Here’s a description.

I have some more information. Every time I open Tbird it re-creates the “Blogs & News Feeds” account. I deleted this account. Then I clicked on a link in a message and Tbird re-created the “Blogs & News Feeds” account. I click again and it tells me that the link is an invalid feed (seems true).

So Tbird thinks ordinary URLs should be RSS URLs and it always wants the RSS account to be present. I can’t find anything on this kind of behavior. But this might be the crux of my problem.

I have found a fix. See Martin Brinkmann’s article

for the procedure. Note that to open the Config Editor you now have to open Preferences, select Advanced, and then click the “Config Editor” button at the bottom.
This fix also seems to have fixed the Blogs & News account problem since URLs are no longer treated as RSS feeds.
I’m sorry I jumped to the conclusion about apparmor, but that did solve the problem the first time. Thanks to you all for your helpful replies. I might have let this languish if you hadn’t posted your responses which motivated me to dig in the right direction.

I am glad you found the problem. It is curious, though. This is the setting I used to turn links “off.” The default is to allow links, i.e. set to “true.” Consequently, it did not occur to me that was what you were suddenly seeing.