Lightmass crashes every build

Can you post your DxDiag here? This file includes your system specs and driver information that could be helpful in seeing if anything stands out.

You may want to try re-installing the engine. If you’re not able to open the Swarm Agent in Windows without the program crashing that could be a problem with the installation, that the VS2015 pre-requisites are not installed properly, the .NET framework is not up to date, and probably a couple of other things to check as well.

Give the re-install a try and see if that resolves it.