Easily With The Most Simple Solutions Fix Error Code 1603 for Office 2021 or Office 2019 Or Microsoft 365. When you install Office on windows 11 or windows 10, you may see error code 1603 if an earlier installation of Office 365/2021/2019 is failed. Here is some process that you can try to fix the issue. But before proceeding ahead first look the most common causes of this office 365/2021/2019 error code 1603 below
Check if the Old office app is already installed on the PC. If so, uninstall and reinstall the app
Install the package to a folder that is not encrypted.
Grant Full Control permissions to the SYSTEM User Account
Firewall or antivirus software might be blocking the Office installation.