We do not recommend using other programs to clean Firefox because they could corrupt the files. Also, the browser can clean itself. [https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode Start Firefox using Troubleshoot(Safe) Mode] {web link} A small dialog should appear. Click '''Start In Troubleshoot(Safe) Mode''' (not Refresh). Is the problem still there? ----------- Go to the [https://addons.mozilla.org/en-US/firefox/ Mozilla Add-ons Web Page] {web Link} (There’s a lot of good stuff here) and search for a download manager. This download manager works separately from the browser. The browser tells it what to download, and off it goes. http://www.freedownloadmanager.org It is a powerful modern download accelerator and organizer for Windows and Mac.