Did you get the full installer from; http://www.mozilla.org/en-US/firefox/all/ ?

Note: Some protection programs don't like the update/install stubs.

I tried to download from here: https://www.mozilla.org/en-US/firefox/new/

And I get the same error message: Couldn't download -- virus scanned failed

Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

Have you tried to disable your protection programs? What programs are you using?

I tried to download from here: https://www.mozilla.org/en-US/firefox/new/

And I get the same error message: Couldn't download -- virus scanned failed

The exact error message is: Couldn't download -- virus scanned failed

I disabled the firefall of McAfee and tried to install again, and got the same exact error message: Couldn't download -- virus scanned failed.

Disable McAfee totally. Then download the file. After, reenable McAfee.

Also, contact McAfee support.

How do I disable McAfee totally?

Contact McAfee support.