diff --git a/.gitignore b/.gitignore
index b275fef..8a10068 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,6 +10,10 @@
 External/Vulkan-Tools
 External/VulkanSamples
 
+# Vulkan CTS testing artifacts
+Scripts/TestResults.qpa
+Scripts/shadercache.bin
+
 # Mac OS X Finder
 .DS_Store
 
diff --git a/Demos/Cube/Cube.xcodeproj/xcshareddata/xcschemes/Cube-macOS.xcscheme b/Demos/Cube/Cube.xcodeproj/xcshareddata/xcschemes/Cube-macOS.xcscheme
index e7696f2..fc957fc 100644
--- a/Demos/Cube/Cube.xcodeproj/xcshareddata/xcschemes/Cube-macOS.xcscheme
+++ b/Demos/Cube/Cube.xcodeproj/xcshareddata/xcschemes/Cube-macOS.xcscheme
@@ -62,7 +62,8 @@
       savedToolIdentifier = ""
       useCustomWorkingDirectory = "NO"
       debugDocumentVersioning = "YES">
-      <MacroExpansion>
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
          <BuildableReference
             BuildableIdentifier = "primary"
             BlueprintIdentifier = "A9B53B0F1C3AC0BE00ABC6F6"
@@ -70,7 +71,7 @@
             BlueprintName = "Cube-macOS"
             ReferencedContainer = "container:Cube.xcodeproj">
          </BuildableReference>
-      </MacroExpansion>
+      </BuildableProductRunnable>
    </ProfileAction>
    <AnalyzeAction
       buildConfiguration = "Debug">
diff --git a/Docs/Whats_New.md b/Docs/Whats_New.md
index d956204..64df3cc 100644
--- a/Docs/Whats_New.md
+++ b/Docs/Whats_New.md
@@ -38,9 +38,11 @@
 - On command buffer submission failure, if `MVKConfiguration::resumeLostDevice` enabled,  do not release 
   waits on `VkDevice`, and do not return `VK_ERROR_DEVICE_LOST`, unless `VkPhysicalDevice` is also lost.
 - Fix inconsistent handling of linear attachment decisions on Apple Silicon.
+- Fix small memory leak during swapchain creation.
 - Protect against crash when retrieving `MTLTexture` when `VkImage` has no `VkDeviceMemory` bound.
 - Adjust some `VkPhysicalDeviceLimits` values for Vulkan and Metal compliance. 
 - Fix internal reference from `SPIRV_CROSS_NAMESPACE_OVERRIDE` to `SPIRV_CROSS_NAMESPACE`.
+- Add `Scripts/runcts` script as a convenience for running Vulkan CTS tests.
 - Support _Xcode 13_ SDK APIs and build settings.
 
 
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.h b/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.h
index c813fa6..18d2d24 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.h
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.h
@@ -201,6 +201,9 @@
     /** Returns whether this attachment should be cleared in the subpass. */
     bool shouldUseClearAttachment(MVKRenderSubpass* subpass);
 
+    /** If this is a depth attachment, the stencil load op may be different than the depth load op. */
+	VkAttachmentLoadOp getAttachmentStencilLoadOp() const;
+
 	/** Constructs an instance for the specified parent renderpass. */
 	MVKRenderPassAttachment(MVKRenderPass* renderPass,
 							const VkAttachmentDescription* pCreateInfo);
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.mm b/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.mm
index 0443597..332efd1 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKRenderPass.mm
@@ -425,7 +425,10 @@
 		MVKPixelFormats* pixFmts = _renderPass->getPixelFormats();
 		MTLPixelFormat mtlDSFmt = _renderPass->getPixelFormats()->getMTLPixelFormat(getDepthStencilFormat());
 		if (pixFmts->isDepthFormat(mtlDSFmt)) { cAtt.aspectMask |= VK_IMAGE_ASPECT_DEPTH_BIT; }
-		if (pixFmts->isStencilFormat(mtlDSFmt)) { cAtt.aspectMask |= VK_IMAGE_ASPECT_STENCIL_BIT; }
+		if (pixFmts->isStencilFormat(mtlDSFmt) &&
+			_renderPass->_attachments[attIdx].getAttachmentStencilLoadOp() == VK_ATTACHMENT_LOAD_OP_CLEAR) {
+			cAtt.aspectMask |= VK_IMAGE_ASPECT_STENCIL_BIT;
+		}
 		if (cAtt.aspectMask) { clearAtts.push_back(cAtt); }
 	}
 }
@@ -720,6 +723,10 @@
 	return (_info.loadOp == VK_ATTACHMENT_LOAD_OP_CLEAR);
 }
 
+VkAttachmentLoadOp MVKRenderPassAttachment::getAttachmentStencilLoadOp() const {
+	return _info.stencilLoadOp;
+}
+
 void MVKRenderPassAttachment::validateFormat() {
 	// Validate pixel format is supported
 	MVKPixelFormats* pixFmts = _renderPass->getPixelFormats();
diff --git a/MoltenVK/MoltenVK/Utility/MVKBlockObserver.m b/MoltenVK/MoltenVK/Utility/MVKBlockObserver.m
index af58a6c..c0314e9 100644
--- a/MoltenVK/MoltenVK/Utility/MVKBlockObserver.m
+++ b/MoltenVK/MoltenVK/Utility/MVKBlockObserver.m
@@ -47,6 +47,7 @@
 
 - (void)dealloc {
 	[self stopObserving];
+	[_block release];
 	[super dealloc];
 }
 
diff --git a/MoltenVKPackaging.xcodeproj/project.pbxproj b/MoltenVKPackaging.xcodeproj/project.pbxproj
index 4a92ac4..c617396 100644
--- a/MoltenVKPackaging.xcodeproj/project.pbxproj
+++ b/MoltenVKPackaging.xcodeproj/project.pbxproj
@@ -195,6 +195,7 @@
 		A9C70F45221B04C800FBA31A /* create_dylib_ios.sh */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = create_dylib_ios.sh; sourceTree = "<group>"; };
 		A9CBBFF924F8A1EB006D41EF /* package_moltenvk_xcframework.sh */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = package_moltenvk_xcframework.sh; sourceTree = "<group>"; };
 		A9DA8341218A198C002AA662 /* .gitignore */ = {isa = PBXFileReference; lastKnownFileType = text; path = .gitignore; sourceTree = "<group>"; };
+		A9DDBF8C26827F02005DD991 /* runcts */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = runcts; sourceTree = "<group>"; };
 		A9FC5F60249D2ED3003CB086 /* package_all.sh */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = package_all.sh; sourceTree = "<group>"; };
 		A9FC5F64249D3778003CB086 /* create_dylib_tvos.sh */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = create_dylib_tvos.sh; sourceTree = "<group>"; };
 /* End PBXFileReference section */
@@ -250,6 +251,7 @@
 				A92EF7C721856EA200C8B91B /* package_shader_converter_tool.sh */,
 				A92EF7CB21856EA300C8B91B /* package_shader_converter_xcframework.sh */,
 				A92EF7CA21856EA200C8B91B /* package_update_latest.sh */,
+				A9DDBF8C26827F02005DD991 /* runcts */,
 				A92EF7DE2186451700C8B91B /* Makefile */,
 			);
 			path = Scripts;
diff --git a/Scripts/runcts b/Scripts/runcts
new file mode 100755
index 0000000..b088fcf
--- /dev/null
+++ b/Scripts/runcts
@@ -0,0 +1,125 @@
+#!/bin/bash
+
+# Copyright (c) 2016-2021 The Brenwill Workshop Ltd.
+#
+# runcts - This script simplifies running Vulkan CTS tests on MoltenVK.
+#
+# CTS will save temporary output files to the directory this script is located in. It is 
+# recommended that you copy this file to a location where your testing files will be kept.
+# By default, this should be a directory beside the VK-GL-CTS directory. See the description 
+# of the --cts option below for information about locations.
+#
+# Executing a large case list file of CTS tests can take a long time. It is recommended
+# that you run this using caffeinate, as follows:
+#     caffeinate -is ./runcts [-o path] [--cts path] [-p] [--portability] case_list_file
+#
+#
+# macOS usage: ./runcts [-o path] [--cts path] [-p] [--portability] case_list_file
+#
+#     case_list_file
+#         The path to the file that contains a list of the CTS test cases to run.
+#
+#     -o path
+#         The path to the file to write the test results. If this option is not provided, 
+#         the results will be written to an output text file with the same name as the 
+#         case_list_file, with "-results.txt" appended. CTS will also output several
+#         working temporary files into the directory holding this script.
+#
+#     --cts path
+#         The path to the directory containing the built CTS executable.
+#         If this parameter is not provided, it defaults to:
+#         "../../VK-GL-CTS/build/external/vulkancts/modules/vulkan/Debug".
+#            
+#      -p
+#         Same as the --portability option.
+#
+#      --portability
+#         Indicates that this testing is for testing conformance with the 
+#         Vulkan Portability initiative. MoltenVK will advertise support for
+#         only Vulkan 1.0, and only the following extensions:
+#             VK_KHR_get_physical_device_properties2
+#             VK_KHR_portability_subset
+#             VK_MVK_moltenvk
+#
+
+cts_vk_dir="../../VK-GL-CTS/build/external/vulkancts/modules/vulkan/Debug"
+caselist_file=""
+results_file=""
+is_portability=""
+
+while (( "$#" )); do
+  case "$1" in
+       -o)
+         results_file="${2}"
+         shift 2
+         ;;
+       --cts)
+         cts_vk_dir="${2}"
+         shift 2
+         ;;
+       -p | --portability)
+         is_portability="Y"
+         shift 1
+         ;;
+       -*|--*=)
+         echo "Error: Unsupported option $1. See usage instructions in body of this script." >&2
+         exit 1
+         ;;
+       *)
+         caselist_file="${1}"
+         shift 1
+         ;;
+  esac
+done
+
+if [ "${caselist_file}" == "" ]; then 
+	echo "Error: No caselist file specified. See usage instructions in body of this script." >&2
+	exit 1
+fi
+
+if [ "${results_file}" == "" ]; then
+	results_file="${caselist_file}-results.txt"
+fi
+
+
+# -------------- MoltenVK configuration --------------------
+
+# As documented above, the portability option restricts to Vulkan 1.0 and a very limited set of extensions.
+# The values used here are documented in vk_mvk_moltenvk.h.
+# - MVK_CONFIG_API_VERSION_TO_ADVERTISE = VK_API_VERSION_1_0 (4194304)
+# - MVK_CONFIG_ADVERTISE_EXTENSIONS selects support for a very limited set of extensions,
+#   using a bit-or of values in MVKConfigAdvertiseExtensions (extension list documented above).
+if [ "${is_portability}" != "" ]; then
+	export MVK_CONFIG_API_VERSION_TO_ADVERTISE=4194304
+	export MVK_CONFIG_ADVERTISE_EXTENSIONS=0xA
+fi
+
+export METAL_DEVICE_WRAPPER_TYPE=1
+export METAL_ERROR_MODE=3
+export METAL_DEBUG_ERROR_MODE=3
+
+# ----- MoltenVK config settings ------
+export MVK_CONFIG_LOG_LEVEL=0
+export MVK_DEBUG=0
+
+# Additional MoltenVK configuration can be set here by 
+# editing below, or can be set before calling this script.
+export MVK_CONFIG_RESUME_LOST_DEVICE=1
+export MVK_CONFIG_FAST_MATH_ENABLED=0
+export MVK_CONFIG_USE_METAL_ARGUMENT_BUFFERS=0
+export MVK_CONFIG_FORCE_LOW_POWER_GPU=0
+
+
+# -------------- Operation --------------------
+
+echo Testing started at `date +%r`
+start_time=${SECONDS}
+
+"${cts_vk_dir}/deqp-vk"                    \
+--deqp-archive-dir="${cts_vk_dir}/.."      \
+--deqp-log-images=disable                  \
+--deqp-log-shader-sources=disable          \
+--deqp-caselist-file="${caselist_file}"    \
+&> "${results_file}"
+
+echo Testing complete in $(($SECONDS - $start_time)) seconds