Crash in Unreal Editor 4.12 P3 with -vulkan flag

I’m running windows 7 here, 4.12 Preview 3 compiled from source (with Vulkan SDK already installed) with a GeForce GTX 980. Normal editor runs fine, and I can preview in Vulkan PIE mode. I crash when adding the -vulkan flag. Stack is too big for the comment, so I attached a text file. Top error is:

Fatal error: [File:C:\UnrealEngine-4.12.0-preview-3\Engine\Source\Runtime\VulkanRHI\Private\VulkanUtil.cpp] [Line: 444] vkCreateSwapchainKHR(Device.GetInstanceHandle(), &SwapChainInfo, nullptr, &SwapChain) failed, VkResult=-1000011001 at C:\UnrealEngine-4.12.0-preview-3\Engine\Source\Runtime\VulkanRHI\Private\VulkanSwapChain.cpp:191 with error VK_ERROR_VALIDATION_FAILED_EXT

Hey Rising2014,

We have had a good few reports in regards to the Vulkan flag causing a crash. We are working hard to resolve these issues and get a fix in before the official release of 4.12, but I cannot guarantee this will be the case as there are sometimes outliers that can cause things to break as well.

With that said, could you provide me with your ‘dxdiag’ and some simple steps to reproduce this error on my end. You can also provide me with your full logs in a zipped folder so the size is manageable.

Cheers,