Fatal error: unexpected failure starting build:

[jerrymarino]

This crash happens when button mashing the play button in Xcode and a build is in progress and emitting errors

Application Specific Information:
ProductBuildVersion: 11B500
Fatal error: unexpected failure starting build: file /Library/Caches/com.apple.xbs/Sources/XCBuild/XCBuild-15509/XCBuild/XCBBuildServiceSession.swift, line 110

Thread 0:: Dispatch queue: CGImageProviderCallbackQueue
0   libsystem_kernel.dylib              0x00007fff70bc8976 kevent_id + 10
1   libdispatch.dylib                   0x00007fff70a48844 _dispatch_kq_poll + 247
2   libdispatch.dylib                   0x00007fff70a492fe _dispatch_event_loop_wait_for_ownership + 498
3   libdispatch.dylib                   0x00007fff70a397ab __DISPATCH_WAIT_FOR_QUEUE__ + 270
4   libdispatch.dylib                   0x00007fff70a3940e _dispatch_sync_f_slow + 171
5   com.apple.CoreImage                 0x00007fff39ee57a3 CI::MetalContext::compute_quad(unsigned int, CI::MetalMainProgram const*, CGSize const&, void const**, unsigned long) + 293
6   com.apple.CoreImage                 0x00007fff39edfa78 CI::MetalContext::render_node(CI::TileTask*, CI::ProgramNode*, CGRect const&, CGRect const&, void const**, __IOSurface**, unsigned long) + 932
7   com.apple.CoreImage                 0x00007fff39edf487 CI::MetalContext::render_root_node(CI::TileTask*, CI::ProgramNode*, CGRect const&, void () block_pointer) + 243
8   com.apple.CoreImage                 0x00007fff39ede8b8 CI::Context::recursive_render(CI::TileTask*, CI::Node*, CGRect const&, CI::Node*, bool) + 1612
9   com.apple.CoreImage                 0x00007fff39ede09c CI::Context::render(CI::ProgramNode*, CGRect const&) + 98
10  com.apple.CoreImage                 0x00007fff3a12a2f6 invocation function for block in CI::image_get_bitmap(CI::Context*, CI::Image*, CGRect, CGColorSpace*, CI::Bitmap*, CI::RenderDestination const*) + 1378
11  com.apple.CoreImage                 0x00007fff39ed3ec8 CI::recursive_tile(CI::RenderTask*, CI::Context*, CI::RenderDestination const*, char const*, CI::Node*, CGRect const&, CI::PixelFormat, CI::swizzle_info const&, CI::TileTask* (CI::ProgramNode*, CGRect) block_pointer) + 3247

[wjk]

@jerrymarino FYI the stack trace you provided doesn’t help any; it's the wrong thread. Look for the label "Thread n crashed::" and copy that stack.