During compile, it freezes and says “not responding”.

Just like your parents telling you that you can be anything you want, it’s lying to you. This happens when Windows cannot process anything else, so it thinks it’s crashed. Open Task Manager before a compile. Watch the processes VVIS.exe and VRAD.exe. They will be using 100% CPU during a compile. It should be noted that this only happens on older version of Hammer that use the embedded compiler. Newer versions that use the Command Prompt window compiler don’t have this issue. You may also try to use some 3rd part compiler interface tools such as CompilePal

Command Prompt Compiler

Embedded Compiler