When I play my game when testing then press escape the game crashes? Any idea how to fix this?

[anonymous_user_90a6966c]

It gives this error: Fatal error: [File:D:\BuildFarm\buildmachine_++UE4+Release-4.11\Engine\Source\Runtime\Core\Private\Windows\WindowsPlatformMisc.cpp] [Line: 409] Pure virtual function being called.