Firefox URL handler does nothing



Clicking on download links attempts to open the file with “Url Handler Script”, but this does nothing and provides no feedback; not even an error message.

I get the following message in my system log:

May 8 22:17:16 localhost firefox_firefox.desktop[26395]: user-open error: no such file or directory

Any ideas what it is trying to do so I can diagnose this further? There seem to be two bugs, that “Url Handler Script” is failing to do anything useful, and that the failure is not being reported back to Firefox or is being ignored.


Can you elaborate on what you are trying to do exactly, and which versions of the core snap and firefox snap you are running, on which distribution?

I am able to download files from web pages and open them from the firefox snap (59.0.2-1 from the stable channel, on Ubuntu 18.04).


I am running both core and firefox from stable. Yes, I know it normally works as it should, as I can create a clean user, login, and things work fine. It is something to do with my primary account’s setup. But I don’t know what, as I have no idea what firefox is doing when it hands something off to “Url Handler Script”. I assume this is some helper somewhere that sneaks the URL out of containment via DBUS or some interface, but I can’t find any useful info to help me diagnose where things are failing or why Firefox is unaware that things are failing. The only feedback is the message in system.log, which is only helpful at pointing me to something inside the snap (so some setting in my Firefox profile, which I pulled in from from the non-snap install).

If it is unclear, this is any time Firefox needs to hand things off to an external process, such as clicking a PDF link. Firefox gives me the choice to save it, or hand it off to something else, and that something else is “Url Handler Script”.


Ah, I see what you mean now. Note that a link to a PDF should open and render the PDF directly in firefox, so that’s probably not a good example (if it doesn’t, it’s a separate issue).

I am able to reproduce the issue if I click on a link to e.g. a doc file. Opening the file with the default “Url Handler Script” results in “user-open error: no such file or directory”.

If I select a different application (e.g. libreoffice writer, I think this requires the libreoffice snap to be installed), the file doesn’t open either, but the error is different: “/usr/bin/env: ‘/tmp/mozilla_osomon0/sample-1.doc’: Permission denied”. This is a different issue that is being discussed in another thread.


I filed bug 1461759 to track the issue upstream.