This seems to be a pretty commonly Google question, but one for which there are no answers.

http://www.linuxquestions.org/questions/linux-software-2/firefox-download-mime-types-378902 http://www.birkit.com/content/kubuntu-linux/internet/firefox/fix-file-associations-in-firefox.html

Being three links amongst the many.

The gist of what I want to accomplish is to have Firefox understand the file associations I download without me having to manually map all of them myself. Gnome knows the file extensions, so I would have expected that Firefox could just use the already-known file mappings there to open the right stuff (as I presume Chrome does). But it doesn't. At least not for me, using Firefox 4, and not by default. When I click on a downloaded file right now, Firefox always has to ask me what application should be used to open the file.

A handful of Google results tell me that I can reassociate my file extensions by deleting ~/.mozilla/firefox/[profile name]/mimeTypes.rdf, but while deleting that file does in fact result in a new mimeTypes file being generated, the new mimeTypes is just as barren as the old one had been.

Based on the amount of unanswered Qs on the Googlesphere, I know this is a very common problem for Ubuntu users, but it seems to be one for which nobody has chimed in with a good solution. Maybe Superuser can finally be the panacea for us all?


You must install ubufox extension try sudo apt-get install ubufox on a terminal. That transitional dummy package associated file extensions to firefox. Here's the link https://launchpad.net/ubufox

  • 3
    Could you add a little more information about what ubufox is and why it would be helpful, possibly with a link to their website? That would make your answer much more helpful. Thanks! – nhinkle Apr 20 '11 at 23:07
  • @wbharding so have you solved your problem? – afarazit May 8 '11 at 11:11
  • Didin't work for me on ubuntu 18.04 – Laurent Sep 26 '18 at 23:11

As originally stated here:

  1. Stop firefox if it is running
  2. Delete or rename the mimetypes cache (where firefox keeps its file association settings):

    $ rm ~/.mozilla/firefox/<yourprofile>/mimeTypes.rdf
  3. Start firefox again

  4. Download any file if you had not done this before
  5. Open that file from the “Tools > Downloads” menu (by right-clicking on it and selecting “Open“). When asked to choose the application for opening the file, browse to “/usr/bin/xdg-open“. then check the checkbox to “Remember your choice“.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.