The answer is . Many enterprise environments, manufacturing systems, and embedded device projects (think Windows CE, older .NET Framework versions, or specific C++ runtimes) are still locked to this toolchain.
The installer is ignoring your offline folder and looking for a network cache. Fix: Run the installer with the --noweb switch. visual studio 2015 update 3 offline installer
You can grab the official ISO directly from the Microsoft servers (login required). The answer is