This usually happens if a web server doesn't send the file with a valid image MIME type, but with a generic MIME type like application/octet-stream or as Content-Disposition:attachment.

• https://addons.mozilla.org/firefox/addon/live-http-headers/

As I wrote in original post, it's not a problem with the site. I've already eliminated that possibility by using FF on another system. This is an issue with settings in FF.

What kind of files are you trying to download? Did you check how the servers sends the files?

You can 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

(I will remove the solution for now as you still seem to have the issue)

OP, did you ever get a solution to this problem? It's driving me nuts having to specify a download destination then go into a program to open the file I just downloaded!! Have tried deleting file types .rdf and no success either!

Tahl said

OP, did you ever get a solution to this problem? It's driving me nuts having to specify a download destination then go into a program to open the file I just downloaded!! Have tried deleting file types .rdf and no success either!

I'm not sure of the solution on Windows. But this worked for me on Linux. I needed to edit mimeTypes.rdf

See the links below for details. The first one was someone having a problem with Transmission. I was having a problem with ktorrent, so I just adapted that. If you're having a problem with a different file type, then you'll need to adapt it differently. But the general idea is the same.

http://askubuntu.com/questions/384375/how-can-i-get-firefox-to-open-torrent-files-with-transmission http://forums.mozillazine.org/viewtopic.php?f=9&t=1706945

Also, I suspect that FlashGot or some similar download manger plugin was responsible for screwing this up. I haven't confirmed it yet, but I've seen some things that make me suspect it.