User Agent: Mozilla/5.0 (X11; Linux i686; rv:27.0) Gecko/20100101 Firefox/27.0 (Beta/Release) Build ID: 20131207004003 Steps to reproduce: In about:support pushed the Profile Directory Open Directory button Actual results: ** (firefox:3869): WARNING **: Cannot launch default application: No application is registered as handling this file Expected results: I don't really know what was supposed to happen, that is why I tried it.

It's supposed to start a file manager with the profile directory open.

(works for me here with 2013-12-08-03-02-04-mozilla-central-firefox-28.0a1.en-US.linux-x86_64)

Same problem with Iceweasel. Don't know why it doesn't work in some Linuxes. All I have is Debian.

We currently call nsIFile.reveal: http://mxr.mozilla.org/mozilla-central/source/toolkit/content/aboutSupport.js?rev=3ac7afad5449#676 Maybe we call launch instead: http://mxr.mozilla.org/mozilla-central/source/xpcom/io/nsIFile.idl?rev=07b29d7938d3#452 launch works for me on OS X (just like reveal does). We'd need to test on other platforms of course.

Hmm, actually this looks like https://bugzilla.mozilla.org/show_bug.cgi?id=680798. Dan, could you take a look at that bug and see if it might apply to what you're seeing?

Yes, getting ** (iceweasel:16124): WARNING **: Cannot launch default application: No application is registered as handling this file in 37.0~a2+20150201004024-1