Comodo 4.1.150349.920

I already intalled this comodo internet security about a week ago. Until today I cannot update the antivirus. The update always failed after downloading 40% of the update. Is there any solution for my problem?

I can’t find it at the moment, but I think you can download the definition file on it’s own, and update manually.

You can download the complete database from the bottom of this page:

Then follow the steps from this page to replace it:
https://forums.comodo.com/empty-t47164.0.html

Hopefully this solves your problem and you’ll be able to update normally from now on.

I’ve done the manual update, but the antivirus status is never updated and every time I connect internet, it always automatically update and failed after downloading about 84 Mb of the update. Is there any way to turn off automatic update?

Yes, go to Antivirus / Real Time Scanning. There should be an option to 'Automatically update virus database before scanning.

If you disable this option I don’t think Comodo Antivirus will update automatically.