How to solve the error code 0x80070003: Invalid installation source during Office 2021 installation

There are several possible solutions to the error code 0x80070003 during Office 2021 installation:

1. Check your internet connection: Make sure you have a stable internet connection and try to download and install Office 2021 again.
2. Disable antivirus software: Sometimes, antivirus software can interfere with the installation process. Try disabling your antivirus software temporarily and then try to install Office 2021 again.
3. Clear the cache: Clear the cache of your browser and try to download and install Office 2021 again.
4. Run the installation as an administrator: Right-click on the Office 2021 installation file and select "Run as administrator" to give the installation process administrative privileges.
5. Use the Microsoft Office Installation Troubleshooter: Microsoft provides a troubleshooter tool that can help diagnose and fix installation issues. Download and run the tool to see if it can resolve the error code 0x80070003.
6. Check your system requirements: Make sure your computer meets the minimum system requirements for Office 2021. If your computer does not meet the requirements, you may need to upgrade your hardware or operating system.