Avast Free anti-virus v10.3.2225 when I downloaded nvidia driver a couple days ago but this been happening for like 1 year+ for me so..... quite a few versions.
Not just nvidia driver as well, a few month ago when I tried to download Java JDK it stopped at 99% and couldn't finish. I had to disable avast and restart from beginning to get the file.
Happened on both my Win 7 SP1 64bit desktop and my win 8 64bit laptop.
Comodo firewall is the only other security software installed.
Always been using Avast, well at least for the past few years.