defaultapp helper64. exe is part of a product called known as Avast Secure Browser and the developer is AVAST Software .
If you think that this file contains a virus or another malware, please download a virus scanner.
If defaultapp helper64. exe is using too much CPU or too much memory in your system, it is possible that your file has been infected with a virus. Installing an antivirus is recommended.
Not all processes can be uninstalled without the help of a 3rd party tool, especially malware. To see if it can be uninstalled, first go to Start > Control Panel > Add/Remove programs and select Avast Secure Browser from the list to remove the process defaultapp helper64. exe from your computer.
If you have any problems with defaultapp helper64. exe, you may try using a registry cleaner or a speed-up software to check, analyze, and fix problems that are affecting the performance of your computer.
You may try contacting AVAST Software, the developer of defaultapp helper64. exe and ask for more information.