When installing avast! Antivirus, do I have to remove old antivirus software?
Thanks for asking this question. Lots of people don’t realize that it’s not a good idea to run two antivirus programs simultaneously. In fact, many antivirus programs will not install if another antivirus is detected on your system. Running multiple antivirus programs on the same computer can cause conflicts resulting in false positive detections, a slowdown in performance, or system instability.
Therefore it is strongly recommended to uninstall all other previously installed antivirus applications before installing avast! on your computer. Most antivirus companies produce a special uninstaller program to remove the antivirus software. It’s best to use these removal tools because typical uninstallation from the Control Panel in Windows can be insufficient in some cases. Some records may still remain in the system and prevent avast! from being correctly installed.
You can find a list of vendors, from Avira to ZoneAlarm, that provide a special removal tool to uninstall their antivirus software on the AVAST FAQ page. We recommend you follow their instructions before proceeding with the uninstallation.