Clicking a http(s) link in Thunderbird does not open the link in the browser

hyperlinkthunderbird

Doubleclicking (or left-click + 'Open link in browser') of hyperlinks in Thunderbird does not work.
This has been going on for at least a year now, across many TB versions (currently 45.3.0).

  • Clicking HTTP or HTTPS links from the browser, my PDF reader, MS Word, desktop shortcuts, whatever, all work.
  • Opening mailto: links from TB works.
  • The click does register: I see it briefly change color, but my browser does not start.

I have checked all things mentioned on the Mozilla support page Hyperlinks in Messages Not Working:

  • Default browser is set OK
  • Actions for HTTP and HTTPS content types in Thunderbirds Tools > Options > Attachments > Incoming are set to 'Use Firefox (default)'
    There are no other 'suspicious entries'
  • Under Help > Troubleshooting > Important Modified Preferences there are no entries for network.protocol-handler.*
    The config editor shows me that network.protocol-handler.external-default is set to default true
  • Starting in Safe Mode does not help

I then did everything in Standard diagnostics that was possible:

  • There was no xul.mfl file
  • Deleted localstore.rdf
  • Deleted the extensions folders (there was no chrome folder)
  • Created a new profile, with MozBackup imported back into it: General settings, Emails, Address books, Bookmarks, Saved passwords, Certificates
  • Removed the test profile, uninstalled TB, removed the TB directory, then reinstalled. It picked up my old profile.

Other things I tried:

  • Martin Brinkmann's Fix for Thunderbird not opening links of setting network.protocol-handler.warn-external.http and network.protocol-handler.warn-external.https to true, thereby forcing me once to pick the browser for opening links, did not help. No prompt came up, the link still did not 'execute'.
  • I ran Nirsofts FileTypesMan, The open settings for .htm and .html are FireFox. The command lines setting is "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -osint -url "%1"
    I reduced that in steps to "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" "%1" without success

What else can I try?

Best Answer

After more searching I found Ray K's suggestion in the mozilla.support.thunderbird Google Groups post Clicking a link in Thunderbird won't open Firefox:

In Tool/Options/Attachments/Incoming, I changed the Actions for incoming HTTP and HTTPS content types from their default 'Use Firefox (default)' to explicitly picking C:\Program Files (x86)\Mozilla FireFox\firefox.exe (it now says 'Use FireFox').

enter image description here This solved the issue.

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