File types and download actions

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When you download a media file, the MIME type determines what action is taken. Files that are associated with certain plugins like Adobe Acrobat, Quicktime, Windows Media Player and Flash will open automatically inside a browser window or in an external player. If no plugin exists, a predefined "helper application" will be used [1] or, if no download action has been defined, you will be prompted to either save the file or open it with a specified application. This article explains how you can change the way downloaded media files are handled.

Download actions

When you click a link to download a file in Firefox or another Mozilla browser, you may see an "Opening" dialog, asking if you want to save the file or open it with a specified application. This means that no plugin is available to handle the file and you haven't previously set a "download action" or "helper application" for that type of file. If you check the option in the "Opening" dialog box to "Do this automatically for files like this from now on" (Firefox) or "Automatically perform this action when handling files of this type" (SeaMonkey/Mozilla Suite), then an entry will appear for that type of file in the Firefox "Download Actions" or SeaMonkey/Mozilla Suite "Helper Applications" listing.

In certain situations, you may not be able to set an automatic download action because the choice to automatically perform the action for future downloads will either not be remembered or the option will be "greyed-out". A misconfigured web server may cause this when the MIME type is incorrectly set as "application/octet-stream" or "text/plain". It also can happen if the server assigns "Content-Disposition: attachment" to the download [2].

Changing download actions

This will not affect media embedded in a web page - only links to the files themselves. Note that certain file extensions may include multiple entries, one for each MIME type associated with that type of file.

Firefox

Firefox 2: Go to "Tools -> Options -> Content / File Types -> Manage...".
Firefox 1.5: Go to "Tools -> Options -> Downloads / Download Actions -> View & Edit Actions".

The Download Actions window will open. (MIME types are not shown by default. Click the icon in the top right corner and select "MIME Type" to display them.)

Select a file type entry and click 'Change Action...'

  • If you want the file to open with the default external program for that file type, select "Open them with the default application"
  • If you want the file to open with an external program other than the default, select "Open them with this application". You will be prompted to select a program.
  • If you want the file to be saved instead of opened, select "Save them on my computer".
  • In some cases, the option to "Use this plugin" will be available. It is the default action if a plugin is found for the file type.

SeaMonkey or Mozilla Suite

Go to "Edit -> Preferences -> Navigator -> Helper Applications". The Helper Applications preferences panel will open.

The entries will be listed as MIME types. Select the entry for the download action you wish to change and click the 'Edit' button to change the download action.

  • If you want the file to open with the default external program for that file type, select "Open it using the default application"
  • If you want the file to open with an external program other than the default, select "Open it with" and use the "Choose..." button to locate the program executable.
  • If you want the file to be downloaded and saved instead of opened, select "Save it to disk".

Note that SeaMonkey and Mozilla Suite do not list plugin actions in the Helper Applications file types listing. You cannot select or disable plugins for file downloads as you can in Firefox.

Removing a download action

To remove a helper application or "save to disk" action, select the file type entry you wish to change, as described above, except click the 'Remove' button instead of the 'Change Action...' or 'Edit' button. The next time a file of that type is downloaded, you will be asked what to do with it. Note that the 'Remove' button does not affect file types that are set to open with plugins.

Resetting download actions

If problems arise or if you want to restore the default set of file download actions, do the following [3]:

  1. Type about:config into the address bar.
  2. Find the preference browser.download.pluginOverrideTypes and, if it is present, right-click on it and select reset.
  3. Find the preference plugin.disable_full_page_plugin_for_types and, if it is present, right-click on it and select reset.
  4. Exit the browser, then open the profile folder (Windows users, read this for help finding it).
  5. Delete (or rename) the file mimeTypes.rdf. Caution: There is also a mimeTypes.rdf file in the program folder. Do not delete it by mistake.

See also

Bug reports

Bug 264492

Please do not comment in bug reports unless you are helping to fix the bug.