Comment 7 for bug 828413

The 'browser.download.dir' key was pointing to my Videos dir, I didn't modify it by hand, it might be caused by some add-on.
At this point, I'd like to suggest creating a tree of dirs under 'Downloads'(ie. Downloads/Video, Downloads/Music and Downloads/Documents) then download manager saves each downloaded file to it's relevant location, just to avoid cluttering the 'Downloads' dir, and it can load slowly, if that dir contained a lot of items.

Anyway, thank you Tim.