Offline installation .Net Framework3.5

[gaojie]

Hello all,

I have added the. net framework 3.5 component to the installation package. There is no problem installing it when the computer is connected to the network, but it cannot be automatically installed when the computer is disconnected. How can I solve this problem?

Thanks,

Jane

[shunt]

Microsoft altered the way that .NET 3.5 was installed, specifically that NET 3.5 is now supplied as a Windows Feature which by default is disabled on modern OS.
This means that we either have to enable the NET 3.5 feature through Windows Update - or provide the actual Windows OS Installation Media.

Microsoft double down by stating that an offline installer is not available for Windows 10.

Install the .NET Framework 3.5 on Windows 11, Windows 10, Windows 8.1, and Windows 8:
https://learn.microsoft.com/en-us/dotnet/framework/install/dotnet-35-windows?redirectedfrom=MSDN 

"The .NET Framework 3.5 SP1 offline installer is available on the .NET Framework 3.5 SP1 Download page and is available for Windows versions prior to Windows 10"

There is a telling warning at the bottom of that page:

"If you're not relying on Windows Update as the source for installing .NET Framework 3.5, you must ensure to strictly use sources from the same corresponding Windows operating system version. Using sources from a different Windows operating system version will either install a mismatched version of .NET Framework 3.5 or cause the installation to fail, leaving the system in an unsupported and unserviceable state."

There is also a knowledge base article you can read here:
https://community.flexera.com/t5/InstallShield-Knowledge-Base/InstallShield-Prerequisites-for-NET-Framework-3-5-SP1-on-Windows/ta-p/4267 

I hope this helps shine some light on the problem.