How to manually Update Avast! Free Antivirus
If your avast antivirus fails to update automatically, you may need to perform a manual update. If the computer to be updated cannot connect to the Internet, you will need a USB flash drive and a separate computer that is able to connect to the Internet.
Visit: http://www.avast.com/en-us/download-update on an Internet connected computer and select download by the update for the version of AVAST that you currently have installed. For most residents this will be “avast! VPS update for version 2014”. You can find out which version of avast you are currently running by launching the application, clicking on the help tab on the left and then selecting “About Avast”.
After the file has finished downloading, it should remain in the bottom download bar of your browser
If this is the computer to be updated, simply click the file in Chrome or Firefox to launch the manual update, or select run if using IE. Select “Run” once again if prompted whether or not you would like to run the file. Simply follow the instructions given by the updater to complete the process.
If the computer to be updated is not the computer you downloaded the update on, you will have to navigate to your download folder (usually located in C:\Users\”username” \Downloads), locate the file (titled “vpsupd”) and move it onto a USB flash drive. Once you have done so, plug the USB flash drive into the computer to be updated, run the vpsupd file and follow the instructions given on screen.