diff --git a/renderdoc/os/linux/linux_callstack.cpp b/renderdoc/os/linux/linux_callstack.cpp
index be59851f7..85edb58f0 100644
--- a/renderdoc/os/linux/linux_callstack.cpp
+++ b/renderdoc/os/linux/linux_callstack.cpp
@@ -45,11 +45,16 @@ class LinuxCallstack : public Callstack::Stackwalk
 		}
 		LinuxCallstack(uint64_t *calls, size_t num)
 		{
-			numLevels = (int)RDCMIN(ARRAY_COUNT(addrs), num);
+			Set(calls, num);
+		}
+		~LinuxCallstack() {}
+
+		void Set(uint64_t *calls, size_t num)
+		{
+			numLevels = num;
 			for(int i=0; i < numLevels; i++)
 				addrs[i] = calls[i];
 		}
-		~LinuxCallstack() {}
 
 		size_t NumLevels() const { return size_t(numLevels); }
 		const uint64_t *GetAddrs() const { return addrs; }
@@ -107,9 +112,9 @@ namespace Callstack
 		return new LinuxCallstack();
 	}
 
-	Stackwalk *Load(uint64_t *calls, size_t numLevels)
+	Stackwalk *Create()
 	{
-		return new LinuxCallstack(calls, numLevels);
+		return new LinuxCallstack(NULL, 0);
 	}
 
 	bool GetLoadedModules(char *&buf, size_t &size)
diff --git a/renderdoc/os/os_specific.h b/renderdoc/os/os_specific.h
index d3b4da325..fbbbffa54 100644
--- a/renderdoc/os/os_specific.h
+++ b/renderdoc/os/os_specific.h
@@ -140,6 +140,9 @@ namespace Callstack
 	{
 	public:
 		virtual ~Stackwalk() {}
+
+		virtual void Set(uint64_t *calls, size_t numLevels) = 0;
+
 		virtual size_t NumLevels() const = 0;
 		virtual const uint64_t *GetAddrs() const = 0;
 	};
@@ -165,7 +168,7 @@ namespace Callstack
 	void Init();
 
 	Stackwalk *Collect();
-	Stackwalk *Load(uint64_t *calls, size_t numLevels);
+	Stackwalk *Create();
 
 	StackResolver *MakeResolver(char *moduleDB, size_t DBSize, string pdbSearchPaths, volatile bool *killSignal);
 
diff --git a/renderdoc/os/win32/win32_callstack.cpp b/renderdoc/os/win32/win32_callstack.cpp
index f04af3d47..28fa8f2c4 100644
--- a/renderdoc/os/win32/win32_callstack.cpp
+++ b/renderdoc/os/win32/win32_callstack.cpp
@@ -42,19 +42,19 @@ class Win32Callstack : public Callstack::Stackwalk
 {
 	public:
 		Win32Callstack();
-		Win32Callstack(uint64_t *calls, size_t numLevels);
+		Win32Callstack(DWORD64 *calls, size_t numLevels);
 		~Win32Callstack();
 
-		size_t NumLevels() const { return m_NumLevels; }
-		const uint64_t *GetAddrs() const { return m_AddrStack; }
+		void Set(DWORD64 *calls, size_t numLevels);
+
+		size_t NumLevels() const { return m_AddrStack.size(); }
+		const uint64_t *GetAddrs() const { return &m_AddrStack[0]; }
 	private:
 		Win32Callstack(const Callstack::Stackwalk &other);
 
 		void Collect();
 
-		size_t m_NumLevels;
-		DWORD64 *m_AddrStack;
-		DWORD64 *m_AllocStack;
+		vector<DWORD64> m_AddrStack;
 };
 
 class Win32CallstackResolver : public Callstack::StackResolver
@@ -333,9 +333,8 @@ void Win32Callstack::Collect()
 		stack32.erase(stack32.begin());
 	}
 
-	m_NumLevels = stack32.size();
-	m_AllocStack = m_AddrStack = new DWORD64[m_NumLevels];
-	for(size_t i=0; i < m_NumLevels; i++)
+	m_AddrStack.resize(stack32.size());
+	for(size_t i=0; i < stack32.size(); i++)
 		m_AddrStack[i] = (DWORD64)stack32[i];
 }
 
@@ -343,24 +342,24 @@ Win32Callstack::Win32Callstack()
 {
 	bool ret = InitDbgHelp();
 
-	m_AllocStack = m_AddrStack = NULL;
-	m_NumLevels = 0;
-
 	if(ret && renderdocBase != NULL)
 		Collect();
 }
 
 Win32Callstack::Win32Callstack(DWORD64 *calls, size_t numLevels)
 {
-	m_NumLevels = numLevels;
-	m_AllocStack = m_AddrStack = new DWORD64[m_NumLevels];
-	for(size_t i=0; i < m_NumLevels; i++)
+	Set(calls, numLevels);
+}
+
+void Win32Callstack::Set(DWORD64 *calls, size_t numLevels)
+{
+	m_AddrStack.resize(numLevels);
+	for(size_t i=0; i < numLevels; i++)
 		m_AddrStack[i] = calls[i];
 }
 
 Win32Callstack::~Win32Callstack()
 {
-	SAFE_DELETE_ARRAY(m_AllocStack);
 }
 
 wstring Win32CallstackResolver::pdbBrowse(wstring startingPoint)
@@ -762,9 +761,9 @@ namespace Callstack
 		return new Win32Callstack();
 	}
 
-	Stackwalk *Load(uint64_t *calls, size_t numLevels)
+	Stackwalk *Create()
 	{
-		return new Win32Callstack(calls, numLevels);
+		return new Win32Callstack(NULL, 0);
 	}
 
 	StackResolver *MakeResolver(char *moduleDB, size_t DBSize, string pdbSearchPaths, volatile bool *killSignal)
diff --git a/renderdoc/serialise/serialiser.cpp b/renderdoc/serialise/serialiser.cpp
index 5e4f95f3f..480363489 100644
--- a/renderdoc/serialise/serialiser.cpp
+++ b/renderdoc/serialise/serialiser.cpp
@@ -131,7 +131,7 @@ void Serialiser::Reset()
 	m_Indent = 0;
 
 	SAFE_DELETE_ARRAY(m_pCallstack);
-	SAFE_DELETE_ARRAY(m_pResolver);
+	SAFE_DELETE(m_pResolver);
 	if(m_Buffer)
 	{
 		FreeAlignedBuffer(m_Buffer);
@@ -392,10 +392,10 @@ void Serialiser::InitCallstackResolver()
 
 void Serialiser::SetCallstack(uint64_t *levels, size_t numLevels)
 {
-	SAFE_DELETE(m_pCallstack);
+	if(m_pCallstack == NULL)
+		m_pCallstack = Callstack::Create();
 
-	if(levels != NULL && numLevels != 0)
-		m_pCallstack = Callstack::Load(levels, numLevels);
+	m_pCallstack->Set(levels, numLevels);
 }
 
 void Serialiser::CreateResolver(void *ths)
diff --git a/renderdoc/serialise/serialiser.h b/renderdoc/serialise/serialiser.h
index 57e0b3380..ff8b6310c 100644
--- a/renderdoc/serialise/serialiser.h
+++ b/renderdoc/serialise/serialiser.h
@@ -324,7 +324,7 @@ class Serialiser
 		// get the callstack associated with the last scope
 		Callstack::Stackwalk *GetLastCallstack()
 		{
-			return m_pCallstack;
+			return (m_pCallstack && m_pCallstack->NumLevels() > 0) ? m_pCallstack : NULL;
 		}
 
 		//////////////////////////////////////////