Error Code 30034-4 of Microsoft Office commonly occurs because of an existing installation of MS Office pack in your computer system. Please note that this error is relevant to all the editions of Microsoft 365, office 2021 and Office 2019. You can fix the Office Install Error code 30034-4 by
Firstly, disable the firewall or antivirus temporarily or
Secondly, create an exceptional rule for Microsoft Office installation or update