Task Host is a Windows program, not a virus or malware. You don’t have to worry about it damaging your system. Task Host ensures that previously running programs have been closed correctly to avoid damaging data and programs when you shut down your system.
It is highly recommended that you close all running programs before shutting down or rebooting your computer. However, if you feel that no programs were running before shutting down, you can perform the following steps to solve this “problem”.