Try to rename (or delete) the mimeTypes.rdf file in the Firefox profile folder to reset all file actions.

• http://kb.mozillazine.org/mimeTypes.rdf
• http://kb.mozillazine.org/File_types_and_download_actions#Resetting_download_actions

You can use this button to go to the current Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I tried renaming the file and restarted firefox after it was renamed, but no luck. When trying to open file like jpg or xls for example through my one webmail account it suggests "truecrypt (default)" and gives me no other options. Even if i select correct program to open it with, it still does not have this option listed next time I try to open these files, only 'truecrypt (default)'

any other suggestions?

are there any other config files that handle file associations perhaps?

You would have to check the settings in the truecrypt program if it has taken over file extensions (associations) to see if you can exclude them.

You can also check the related HKEY_CLASSES_ROOT keys in the registry and possibly the MIME database key as well.

• HKEY_CLASSES_ROOT\.xxx

You can check the linked MIME type in the MIME Database registry key.

• HKEY_CLASSES_ROOT\MIME\Database\Content Type\

All changes that you make in the registry editor are applied instantly and that there is no undo possible. You can export key(s) in the registry editor before making changes. If you are not comfortable with editing the Windows registry then it is best to skip editing registry keys.

No, nothing like that, since this association only happens on a certain domain with firefox. If I for example were to download a xls, pdf or jpg form mozilla.org they would all open with the correct software.

Running linux, windows registry stuffz wont help me much

You posted with a Windows 8.1 user agent?

• User Agent: Mozilla/5.0 (Windows NT 6.3; rv:36.0) Gecko/20100101 Firefox/36.0

It is either a setting stored in mimeTypes.rdf or an operating system specific setting of the involved file association. Firefox doesn't come up by itself with a specific application.

What happens if you right-click such a file in a file manager and check what applications are offered and which is the default?

Yes, thats my user-agent changer. Although running linux.

In the system all files have the correct association. The only solution when I try to open files from this one domain is to 'save as' and then go to my download folder in the system and open files manually there.

Are there any other mimeTypes.rdf, other than the one in my home dir perhaps? As I mentioned before, I tried deleting it and restarting FF although the problem persisted.

Did you check this with xdg-mime?

• xdg-mime query default <mime type> (image/png)
• xdg-mime query filetype <file extension> (*.png)

$ xdg-mime query filetype *.png image/png $ xdg-mime query default image/png eog.desktop

(eog: Eye of Gnome) I only mentioned these two as an example.

Did you check this for MIME types and file extensions that cause problems?

PNG is one of the filetype I have problems with

but to take another example: $ xdg-mime query default pplication/pdf evince.desktop

evince is correct, but this also opens with truecrypt.

same for: $ xdg-mime query default pplication/xls libreoffice-calc.desktop

I think that these are location that can effect this:

/usr/share/applications/
/usr/share/mime/ (application/)
~/.local/share/applications/
~/.local/share/mime/  (application/)

Does anything come up up you search these locations for truecrypt?

Running more *|grep truecrypt in the mentioned directories, and very little is returned if any. Nothing regarding the mentioned file types tho.

Are there even rules in firefox allowing for different domains to open files with different programs? I though the programs firefox proposes to open files with were global for all websites. Is this not the case?

Still having issues with this

I have noticed some PDF, JPG, XLS etc on the domain does open with correct program but most do not. For other domains its always the correct programs that open these files. Has never happened that they would try to open with truecrypt as they do on the webmail.

Very confused to how this can be. Bug in firefox?