Sometimes it might become annoying for you and you would like to disable this automatic scanning as it takes a few extra seconds to scan the file and it also causes following problems to a few users:

• It doesnt download a file and gives warning message: “Blocked: Download may contain a virus or spyware“, even you are sure that the file is completely safe.
• The built-in download manager freezes while downloading a file.

1. Open firefox and type to browser “about:config” and press Enter. To confirm, click on I’ll be careful, I promise! button.

2. Type scanwhendone in the Firefox cpanel Filter box ( look at top ). After you type it show something like “browser.download.manager.scanWhenDone” in the results window and ity show value “true”.

3. To change this, double-click on this entry or right-click on it and select “Toggle“. Now your setting value to “False“.

4. You have done. Close firefox and restart again. Now your Firefox will not scan any downloaded file after you download something.