How to fix error code 0x80070003: Invalid installation source for Office 2021

Here are multiple methods to address error code 0x80070003 when installing Office 2021:

1. Verify your internet connection: Ensure your internet connection is stable, then attempt to download and install Office 2021 again.
2. Temporarily disable antivirus software: Antivirus programs can sometimes disrupt the installation process. Temporarily disable your antivirus software and try installing Office 2021 once more.
3. Clear browser cache: Clear your browser's cache, then attempt to download and install Office 2021 again.
4. Run installation with administrative rights: Right-click the Office 2021 installation file and choose 'Run as administrator' to provide the installation process with administrative privileges.
5. Utilize the Microsoft Office Installation Troubleshooter: Microsoft offers a troubleshooting tool to diagnose and resolve installation issues. Download and execute the tool to see if it resolves error code 0x80070003.
6. Confirm system requirements: Ensure your computer meets the minimum system requirements for Office 2021. If it doesn't, you might need to upgrade your hardware or operating system.