This is a frequent D3D Hung crash, similar to [Link Removed] and [Link Removed].
A potential fix for the other crashes was released in 4.14.2, but this crash is still occurring on that release.
Stephen - Repro steps currently unknown. I did experience this once on my home PC after dragging a few static meshes from the Infinity Blade pack into my level and starting to rotate one of them.
Alternate User Provided Repro:
A user reported that switching to wireframe view mode caused the crash.
Fatal error: [Link Removed] [Line: 176] Unreal Engine is exiting due to D3D device being lost. (Error: 0x887A0006 - 'HUNG')
UE4Editor_D3D11RHI!TerminateOnDeviceRemoved() d3d11util.cpp:176
UE4Editor_D3D11RHI!VerifyD3D11Result() d3d11util.cpp:225
UE4Editor_D3D11RHI!FD3D11DynamicRHI::ReadSurfaceDataNoMSAARaw() d3d11rendertarget.cpp:601
UE4Editor_D3D11RHI!FD3D11DynamicRHI::RHIReadSurfaceData() d3d11rendertarget.cpp:949
UE4Editor_RHI!FRHICommandListImmediate::ReadSurfaceData() rhicommandlist.h:2748
UE4Editor_Engine!`FViewport::GetRawHitProxyData'::`31'::EURCMacro_ReadSurfaceCommand::DoTask() unrealclient.cpp:1318
UE4Editor_Engine!TGraphTask<`FViewport::GetRawHitProxyData'::`31'::EURCMacro_ReadSurfaceCommand>::ExecuteTask() taskgraphinterfaces.h:868
UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() taskgraph.cpp:932
UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() taskgraph.cpp:679
UE4Editor_RenderCore!RenderingThreadMain() renderingthread.cpp:319
UE4Editor_RenderCore!FRenderingThread::Run() renderingthread.cpp:440
UE4Editor_Core!FRunnableThreadWin::Run() windowsrunnablethread.cpp:74
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-40202 in the post.