If you still see the error after all this, your Windows image may be too stripped down. Consider a clean install of Windows 10 LTSC or the Virtual Machine route. Good luck, and keep making music.
This does not install the actual .NET libraries. While it may bypass the installer, Cubase might crash later when it tries to call .NET 1.0 functions that don't exist. Use this only as a last resort if you are comfortable with the risk. If you still see the error after all
"Cubase 5 cannot be installed on system with .NET Framework version smaller than 1.0." This does not install the actual
Your system does have .NET capabilities. But Windows 10/11 hides legacy .NET 3.5 (which includes 2.0 and 3.0) behind a "Windows Feature." .NET 1.0 is not even listed there. This is the root of your frustration. "Cubase 5 cannot be installed on system with
Close Regedit. Run the Cubase 5 installer.
Since the installer explicitly asks for version 1.0, we will give it version 1.1 (which is nearly identical and satisfies the check).
.NET 1.0 is 20+ years old and has known security vulnerabilities. Only install it if you are using Cubase 5 strictly offline (disconnected from the internet) or on a dedicated music production machine that never browses the web.