https://support.eset.com/kb3732

This error occurs when remnants of previously installed antivirus software are still present on a system where you are installing ESET Endpoint Security or ESET Endpoint Antivirus.

• If you know which antivirus product was previously installed on your computer, see our list of removal tools for common Windows antivirus software.
   
• If you don't know which antivirus software was installed on your system, click here for instructions to run the ESET AV Remover.