diff --git a/stepmania/src/archutils/Xbox/VirtualMemory.cpp b/stepmania/src/archutils/Xbox/VirtualMemory.cpp
index 4ba672ffcd..3ebb1cc032 100644
--- a/stepmania/src/archutils/Xbox/VirtualMemory.cpp
+++ b/stepmania/src/archutils/Xbox/VirtualMemory.cpp
@@ -5,7 +5,8 @@
 
 VirtualMemoryManager vmem_Manager;
 
-VirtualMemoryManager::VirtualMemoryManager()
+VirtualMemoryManager::VirtualMemoryManager():
+	vmemMutex("VirtualMemory")
 {
 	pages = 0;
 	pageLRU = -1;
@@ -90,6 +91,8 @@ void* VirtualMemoryManager::Allocate(size_t size)
 	if(!inited)
 		return NULL;
 
+	LockMut(vmemMutex);
+
 	unsigned long startPage = -1;
 	unsigned long freeSegments = 0;
 	unsigned long sizeInPages = (size / pageSize) + 1;
@@ -164,6 +167,8 @@ bool VirtualMemoryManager::Free(void *ptr)
 	if(!inited)
 		return false;
 
+	LockMut(vmemMutex);
+
 	// check that the address is within the virtual address bounds
 	if((DWORD)ptr < baseAddress || (DWORD)ptr >= baseAddress + (totalPages * pageSize))
 	{
@@ -214,6 +219,8 @@ bool VirtualMemoryManager::PageFault(void *ptr)
 	if(!inited)
 		return false;
 
+	LockMut(vmemMutex);
+
 	// check that the address is within the virtual address bounds
 	if((DWORD)ptr < baseAddress || (DWORD)ptr >= baseAddress + (totalPages * pageSize))
 	{
@@ -279,6 +286,8 @@ bool VirtualMemoryManager::DecommitLRU()
 	if(!inited)
 		return false;
 
+	LockMut(vmemMutex);
+
 	// choose random LRU
 	pageLRU = rand() % totalPages;
 
@@ -335,6 +344,8 @@ bool VirtualMemoryManager::EnsureFreeMemory(size_t size)
 	if(!inited)
 		return false;
 
+	LockMut(vmemMutex);
+
 	MEMORYSTATUS ms;
 	GlobalMemoryStatus(&ms);
 
@@ -359,6 +370,8 @@ void VirtualMemoryManager::Lock(void *ptr)
 	if(!inited)
 		return;
 
+	LockMut(vmemMutex);
+
 	// check that the address is within the virtual address bounds
 	if((DWORD)ptr < baseAddress || (DWORD)ptr >= baseAddress + (totalPages * pageSize))
 	{
@@ -394,6 +407,8 @@ void VirtualMemoryManager::Unlock(void *ptr)
 	if(!inited)
 		return;
 
+	LockMut(vmemMutex);
+
 	// check that the address is within the virtual address bounds
 	if((DWORD)ptr < baseAddress || (DWORD)ptr >= baseAddress + (totalPages * pageSize))
 	{
diff --git a/stepmania/src/archutils/Xbox/VirtualMemory.h b/stepmania/src/archutils/Xbox/VirtualMemory.h
index 46ad9f1071..bccd4bd552 100644
--- a/stepmania/src/archutils/Xbox/VirtualMemory.h
+++ b/stepmania/src/archutils/Xbox/VirtualMemory.h
@@ -5,6 +5,8 @@
 
 #pragma once
 
+#include "RageThreads.h"
+
 struct vm_page
 {
 	DWORD startAddress; // start address for this page
@@ -49,6 +51,9 @@ protected:
 
 	bool inited;
 	bool logging;
+
+	// mutex to make sure pages aren't allocated/deallocated concurrently
+	RageMutex vmemMutex;
 };
 
 void *valloc(size_t size);