Firefox Quick Tip: When downloads stop working...
Sometimes Firefox freaks out and for no reason at all, the downloads (Ctrl + J) stop working and it doesn’t allow you to download anything while using the browser. Be it a simple image, or an email attachment – nothing can be done.
This problem has happened to me before, and the solution to get the downloads working again (in my case) was very easy – just had to delete one file, the “downloads.rdf” to be more specific, that is suppose to be located in the Profile folder of Firefox.
There might be other solutions to solve the “downloads in Firefox problem” – check this page on the Mozilla Knowledge Base for more information/solutions, such as reseting the download folder.