diff --git a/UnrealFolder/ProjectMobius/Plugins/Hdf5DataPlugin/Source/Hdf5DataPlugin/Private/Hdf5SimulationReader.cpp b/UnrealFolder/ProjectMobius/Plugins/Hdf5DataPlugin/Source/Hdf5DataPlugin/Private/Hdf5SimulationReader.cpp
index 5acbaece0..96c3333a3 100644
--- a/UnrealFolder/ProjectMobius/Plugins/Hdf5DataPlugin/Source/Hdf5DataPlugin/Private/Hdf5SimulationReader.cpp
+++ b/UnrealFolder/ProjectMobius/Plugins/Hdf5DataPlugin/Source/Hdf5DataPlugin/Private/Hdf5SimulationReader.cpp
@@ -23,9 +23,26 @@
 
 #include "Hdf5SimulationReader.h"
 #include "Misc/Paths.h"
+#include "Misc/ScopeLock.h"
 
 DEFINE_LOG_CATEGORY_STATIC(LogHdf5SimulationReader, Log, All);
 
+namespace
+{
+	/**
+	 * The bundled HDF5 library is built without thread safety (Threadsafety: OFF in
+	 * libhdf5.settings), so no two threads may execute HDF5 code concurrently.
+	 * Geometry and trajectory loading both read the same .h5 from different threads,
+	 * so every public reader method serializes on this process-wide lock.
+	 * The lock is recursive on all UE platforms, so public methods may call each other.
+	 */
+	FCriticalSection& GetHdf5LibraryLock()
+	{
+		static FCriticalSection Hdf5LibraryLock;
+		return Hdf5LibraryLock;
+	}
+}
+
 FHdf5SimulationReader::FHdf5SimulationReader()
 {
 }
@@ -37,6 +54,8 @@ FHdf5SimulationReader::~FHdf5SimulationReader()
 
 bool FHdf5SimulationReader::OpenFile(const FString& FilePath)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	// Close any previously open file
 	CloseFile();
 
@@ -58,7 +77,8 @@ bool FHdf5SimulationReader::OpenFile(const FString& FilePath)
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("Failed to open HDF5 file: %s"), *FilePath);
-		H5close();
+		// Do not call H5close() here: it tears down the HDF5 library process-wide,
+		// crashing any other reader that is mid-operation.
 		return false;
 	}
 
@@ -111,10 +131,13 @@ bool FHdf5SimulationReader::OpenFile(const FString& FilePath)
 
 void FHdf5SimulationReader::CloseFile()
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId >= 0)
 	{
 		H5Fclose(FileId);
-		H5close();
+		// Deliberately no H5close(): that shuts down the HDF5 library for the whole
+		// process, not just this file, and other readers may still be active.
 		FileId = -1;
 		DetectedFormat = EHdf5FormatType::Unknown;
 		TimestepCount = 0;
@@ -276,6 +299,8 @@ bool FHdf5SimulationReader::ReadStringAttribute(hid_t GroupId, const char* AttrN
 
 bool FHdf5SimulationReader::ReadMetadata(FHdf5SimulationMetadata& OutMetadata)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -320,6 +345,8 @@ bool FHdf5SimulationReader::ReadMetadata(FHdf5SimulationMetadata& OutMetadata)
 
 bool FHdf5SimulationReader::ReadEntities(TArray<FHdf5EntityData>& OutEntities)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -417,6 +444,8 @@ bool FHdf5SimulationReader::ReadEntities(TArray<FHdf5EntityData>& OutEntities)
 
 bool FHdf5SimulationReader::ReadTimesteps(TArray<float>& OutTimesteps)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -453,6 +482,8 @@ bool FHdf5SimulationReader::ReadTimesteps(TArray<float>& OutTimesteps)
 
 bool FHdf5SimulationReader::ReadSamplesPerTimestep(TArray<int32>& OutSamplesPerTimestep)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -496,6 +527,8 @@ bool FHdf5SimulationReader::ReadSamplesPerTimestep(TArray<int32>& OutSamplesPerT
 
 bool FHdf5SimulationReader::ReadAllSamples(TArray<FHdf5SampleData>& OutSamples, bool* OutHasRotationField, bool* OutHasSpeedField)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -608,6 +641,8 @@ bool FHdf5SimulationReader::ReadAllSamples(TArray<FHdf5SampleData>& OutSamples,
 
 bool FHdf5SimulationReader::ReadSamplesForTimestepRange(int32 StartTimestep, int32 EndTimestep, TArray<FHdf5SampleData>& OutSamples)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -718,6 +753,8 @@ EHdf5FormatType FHdf5SimulationReader::DetectFormat(const FString& FilePath)
 		return EHdf5FormatType::Unknown;
 	}
 
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	FTCHARToUTF8 FilePathUtf8(*FilePath);
 
 	// Check if it's a valid HDF5 file
@@ -731,7 +768,6 @@ EHdf5FormatType FHdf5SimulationReader::DetectFormat(const FString& FilePath)
 	hid_t TempFileId = H5Fopen(FilePathUtf8.Get(), H5F_ACC_RDONLY, H5P_DEFAULT);
 	if (TempFileId < 0)
 	{
-		H5close();
 		return EHdf5FormatType::Unknown;
 	}
 
@@ -750,7 +786,6 @@ EHdf5FormatType FHdf5SimulationReader::DetectFormat(const FString& FilePath)
 	}
 
 	H5Fclose(TempFileId);
-	H5close();
 
 	return Result;
 }
@@ -759,6 +794,8 @@ EHdf5FormatType FHdf5SimulationReader::DetectFormat(const FString& FilePath)
 
 bool FHdf5SimulationReader::ReadJuelichMetadata(FHdf5JuelichMetadata& OutMetadata)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -845,6 +882,8 @@ bool FHdf5SimulationReader::ReadJuelichMetadata(FHdf5JuelichMetadata& OutMetadat
 
 bool FHdf5SimulationReader::ReadJuelichTrajectories(TArray<FHdf5JuelichTrajectoryRecord>& OutRecords)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
@@ -924,6 +963,8 @@ bool FHdf5SimulationReader::ReadJuelichTrajectories(TArray<FHdf5JuelichTrajector
 
 bool FHdf5SimulationReader::ReadWktGeometry(FString& OutWktGeometry)
 {
+	FScopeLock Hdf5Guard(&GetHdf5LibraryLock());
+
 	if (FileId < 0)
 	{
 		UE_LOG(LogHdf5SimulationReader, Error, TEXT("No file is open"));
diff --git a/UnrealFolder/ProjectMobius/Source/MobiusCore/Private/Interfaces/ProjectMobiusInterface.cpp b/UnrealFolder/ProjectMobius/Source/MobiusCore/Private/Interfaces/ProjectMobiusInterface.cpp
index ff01a6a7b..ea026f066 100644
--- a/UnrealFolder/ProjectMobius/Source/MobiusCore/Private/Interfaces/ProjectMobiusInterface.cpp
+++ b/UnrealFolder/ProjectMobius/Source/MobiusCore/Private/Interfaces/ProjectMobiusInterface.cpp
@@ -25,9 +25,48 @@
 #include "Interfaces/ProjectMobiusInterface.h"
 #include "Engine/GameInstance.h"
 #include "GameInstances/ProjectMobiusGameInstance.h"
+#include "Hdf5SimulationReader.h"
+#include "Misc/Paths.h"
 
 // Add default functionality here for any IProjectMobiusInterface functions that are not pure virtual.
 
+namespace
+{
+	/**
+	 * HDF5 simulation files can carry the scene geometry alongside the trajectories in the
+	 * root "wkt_geometry" attribute. When such a file is selected as the pedestrian data
+	 * source, adopt it as the geometry source too so a single selection loads both.
+	 * @param GameInst - Mobius game instance to update
+	 * @param DataPath - Full path of the newly selected pedestrian data file
+	 */
+	void AdoptEmbeddedGeometrySource(UProjectMobiusGameInstance* GameInst, const FString& DataPath)
+	{
+		if (!GameInst || !DataPath.EndsWith(TEXT(".h5"), ESearchCase::IgnoreCase))
+		{
+			return;
+		}
+
+		FHdf5SimulationReader Reader;
+		if (!Reader.OpenFile(DataPath))
+		{
+			return;
+		}
+
+		FString WktGeometry;
+		const bool bHasGeometry = Reader.ReadWktGeometry(WktGeometry) && !WktGeometry.IsEmpty();
+		Reader.CloseFile();
+
+		if (!bHasGeometry)
+		{
+			UE_LOG(LogTemp, Log, TEXT("No embedded geometry in %s, geometry selection left unchanged"), *DataPath);
+			return;
+		}
+
+		GameInst->SetSimulationMeshFilePath(DataPath);
+		GameInst->SetSimulationMeshFileName(FPaths::GetCleanFilename(DataPath));
+	}
+}
+
 UProjectMobiusGameInstance* IProjectMobiusInterface::GetMobiusGameInstance(UWorld* World)
 {
 	if(!World)
@@ -111,6 +150,9 @@ void IProjectMobiusInterface::UpdateMobiusGameInstancePedestrianData(UWorld* Wor
 	
 	// Set the pedestrian data file name
 	MobiusGameInst->SetPedestrianDataFileName(FPaths::GetCleanFilename(CompleteDataPath));
+
+	// HDF5 files can embed the geometry, load it from the same file
+	AdoptEmbeddedGeometrySource(MobiusGameInst, CompleteDataPath);
 }
 
 void IProjectMobiusInterface::GetMobiusGameInstanceMeshDataFile(UWorld* World, FString& OutCompleteDataPath,
diff --git a/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadAgentDataWidget.cpp b/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadAgentDataWidget.cpp
index b10b0056b..9fb947f80 100644
--- a/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadAgentDataWidget.cpp
+++ b/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadAgentDataWidget.cpp
@@ -132,7 +132,7 @@ void ULoadAgentDataWidget::DialogClosed(const FString& AgentFilePath, const FStr
 			Feedback->ReportError(
 				FText::FromString("Invalid Agent Data File"),
 				FText::FromString("Unsupported agent data file type selected."),
-				FText::FromString("Supported types: .json"),
+				FText::FromString("Supported types: .json, .h5"),
 				FText::FromString("Load Agent Data"));
 		}
 		UE_LOG(LogTemp, Warning, TEXT("The file dialog was canceled or an error occurred"));
diff --git a/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadMeshWidget.cpp b/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadMeshWidget.cpp
index ce069e21d..b3218b7a6 100644
--- a/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadMeshWidget.cpp
+++ b/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Private/UI/LoadSave/LoadMeshWidget.cpp
@@ -25,11 +25,33 @@
 #include "UI/LoadSave/LoadMeshWidget.h"
 #include "Subsystems/NativeFileDialogSubsystem.h"
 #include "Subsystems/MobiusUserFeedbackSubsystem.h"
+#include "GameInstances/ProjectMobiusGameInstance.h"
 
 void ULoadMeshWidget::NativeConstruct()
 {
 	Super::NativeConstruct();
 
+	if (UProjectMobiusGameInstance* MobiusGameInst = IProjectMobiusInterface::GetMobiusGameInstance(GetWorld()))
+	{
+		MobiusGameInst->OnMeshFileChanged.AddUniqueDynamic(this, &ULoadMeshWidget::OnGameInstanceMeshFileChanged);
+	}
+}
+
+void ULoadMeshWidget::NativeDestruct()
+{
+	if (UProjectMobiusGameInstance* MobiusGameInst = IProjectMobiusInterface::GetMobiusGameInstance(GetWorld()))
+	{
+		MobiusGameInst->OnMeshFileChanged.RemoveDynamic(this, &ULoadMeshWidget::OnGameInstanceMeshFileChanged);
+	}
+
+	Super::NativeDestruct();
+}
+
+void ULoadMeshWidget::OnGameInstanceMeshFileChanged()
+{
+	// Pull the new path out of the game instance and refresh the text block
+	GetMobiusGameInstanceData();
+	UpdateFileTextBlockTexts();
 }
 
 void ULoadMeshWidget::OnSelectFileButtonClicked()
@@ -132,7 +154,7 @@ void ULoadMeshWidget::DialogClosed(const FString& AgentFilePath, const FString&
 			Feedback->ReportError(
 				FText::FromString("Invalid Mesh File"),
 				FText::FromString("Unsupported mesh file type selected."),
-				FText::FromString("Supported types: .fbx, .obj, .udatasmith, .ifc, .wkt"),
+				FText::FromString("Supported types: .fbx, .obj, .udatasmith, .ifc, .wkt, .h5"),
 				FText::FromString("Load Mesh"));
 		}
 		UE_LOG(LogTemp, Warning, TEXT("The file dialog was canceled or an error occurred"));
diff --git a/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Public/UI/LoadSave/LoadMeshWidget.h b/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Public/UI/LoadSave/LoadMeshWidget.h
index e00fafa83..7c9e35d83 100644
--- a/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Public/UI/LoadSave/LoadMeshWidget.h
+++ b/UnrealFolder/ProjectMobius/Source/MobiusWidgets/Public/UI/LoadSave/LoadMeshWidget.h
@@ -41,6 +41,8 @@ class MOBIUSWIDGETS_API ULoadMeshWidget : public ULoadDataParentWidget
 #pragma region PUBLIC_METHODS
 	// Constructor 
 	virtual void NativeConstruct() override;
+
+	virtual void NativeDestruct() override;
 	
 	/**
 	 * Method to call when the SelectFileButton is clicked
@@ -66,6 +68,13 @@ class MOBIUSWIDGETS_API ULoadMeshWidget : public ULoadDataParentWidget
 	/** Handler for file dialog errors. Displays error popup to user. */
 	UFUNCTION()
 	void OnDialogError(const FString& ErrorTitle, const FString& ErrorMessage);
+
+	/**
+	 * Refresh the displayed path when the geometry file is changed elsewhere, e.g. when an
+	 * HDF5 pedestrian data file supplies its own embedded geometry.
+	 */
+	UFUNCTION()
+	void OnGameInstanceMeshFileChanged();
 #pragma endregion PUBLIC_METHODS
 
 #pragma endregion METHODS