Hello, I'm using Ubuntu (exactly xubuntu 14.04) and it's always my OS who makes updates. Today my OS made me do an update of Firefox (to 43.0 version). Understand it's the Ubuntu/Canonical firefox version. I prefer to use the OS package manager to install applications. And with this new version of firefox, I can't download anything. There is the animation when I click to start a download, but when I display the progress of ongoing downloads, all downloads are just marked as "failed". PDF files works if I choose to display such files (i.e the default firefox behaviour), but if I chose to download it (or to do a "save link as"), I have this trouble. What I tried: 1/ I removed all my add-ons & extensions 2/ I created a new user on my OS to have a "fresh" firefox (to get default firefox parameters) 3/ with my Ubuntu package manager I removed firefox, restarted my computer, reinstalled firefox (still through package manager) But the trouble remains even if I combine #2 & #3 I'm very suprised, I've searched bugs and it seems no one has this trouble. Am I the only one? Do you think the bug would come from the Ubuntu firefox package (though I don't think there is much difference) ? Thanks for your help