This usually happens when using the Web Installer on a shaky connection.
While the .NET Framework is a robust and reliable component of Windows, issues can arise. Here are some common issues with .NET Framework on Windows 7 64-bit systems: net framework for win 7 64 bit
If you are setting up a Windows 7 machine today, is the "gold standard" for compatibility and relative security. It acts as an in-place update for 4.0, 4.5, 4.5.1, etc., meaning installing it covers the requirements for most software asking for those older 4.x versions. This usually happens when using the Web Installer
At least 2 GB (though 4 GB is recommended for 64-bit systems). How to Download and Install .NET Framework 4.8 net framework for win 7 64 bit