diff --git a/renderdoc/driver/d3d12/d3d12_device_wrap.cpp b/renderdoc/driver/d3d12/d3d12_device_wrap.cpp
index 3b465fbf4..b9df5e220 100644
--- a/renderdoc/driver/d3d12/d3d12_device_wrap.cpp
+++ b/renderdoc/driver/d3d12/d3d12_device_wrap.cpp
@@ -864,7 +864,7 @@ bool WrappedID3D12Device::Serialise_CreateDescriptorHeap(
     }
     else
     {
-      ret = new WrappedID3D12DescriptorHeap(ret, this, Descriptor);
+      ret = new WrappedID3D12DescriptorHeap(ret, this, PatchedDesc, Descriptor.NumDescriptors);
 
       GetResourceManager()->AddLiveResource(pHeap, ret);
 
@@ -891,8 +891,8 @@ HRESULT WrappedID3D12Device::CreateDescriptorHeap(const D3D12_DESCRIPTOR_HEAP_DE
 
   if(SUCCEEDED(ret))
   {
-    WrappedID3D12DescriptorHeap *wrapped =
-        new WrappedID3D12DescriptorHeap(real, this, *pDescriptorHeapDesc);
+    WrappedID3D12DescriptorHeap *wrapped = new WrappedID3D12DescriptorHeap(
+        real, this, *pDescriptorHeapDesc, pDescriptorHeapDesc->NumDescriptors);
 
     if(IsCaptureMode(m_State))
     {
diff --git a/renderdoc/driver/d3d12/d3d12_initstate.cpp b/renderdoc/driver/d3d12/d3d12_initstate.cpp
index 7a51dad1b..2807aef8f 100644
--- a/renderdoc/driver/d3d12/d3d12_initstate.cpp
+++ b/renderdoc/driver/d3d12/d3d12_initstate.cpp
@@ -595,7 +595,7 @@ bool D3D12ResourceManager::Serialise_InitialState(SerialiserType &ser, ResourceI
         return false;
       }
 
-      copyheap = new WrappedID3D12DescriptorHeap(copyheap, m_Device, desc);
+      copyheap = new WrappedID3D12DescriptorHeap(copyheap, m_Device, desc, heap->GetNumDescriptors());
 
       D3D12_CPU_DESCRIPTOR_HANDLE handle = copyheap->GetCPUDescriptorHandleForHeapStart();
 
diff --git a/renderdoc/driver/d3d12/d3d12_resources.cpp b/renderdoc/driver/d3d12/d3d12_resources.cpp
index 0e2f5cc73..98dc23f25 100644
--- a/renderdoc/driver/d3d12/d3d12_resources.cpp
+++ b/renderdoc/driver/d3d12/d3d12_resources.cpp
@@ -347,7 +347,8 @@ rdcarray<ID3D12Resource *> WrappedID3D12Resource::AddRefBuffersBeforeCapture(D3D
 
 WrappedID3D12DescriptorHeap::WrappedID3D12DescriptorHeap(ID3D12DescriptorHeap *real,
                                                          WrappedID3D12Device *device,
-                                                         const D3D12_DESCRIPTOR_HEAP_DESC &desc)
+                                                         const D3D12_DESCRIPTOR_HEAP_DESC &desc,
+                                                         UINT UnpatchedNumDescriptors)
     : WrappedDeviceChild12(real, device)
 {
   realCPUBase = real->GetCPUDescriptorHandleForHeapStart();
@@ -356,12 +357,12 @@ WrappedID3D12DescriptorHeap::WrappedID3D12DescriptorHeap(ID3D12DescriptorHeap *r
   SetResident(true);
 
   increment = device->GetUnwrappedDescriptorIncrement(desc.Type);
-  numDescriptors = desc.NumDescriptors;
+  numDescriptors = UnpatchedNumDescriptors;
 
-  descriptors = new D3D12Descriptor[numDescriptors];
+  descriptors = new D3D12Descriptor[desc.NumDescriptors];
 
-  RDCEraseMem(descriptors, sizeof(D3D12Descriptor) * numDescriptors);
-  for(UINT i = 0; i < numDescriptors; i++)
+  RDCEraseMem(descriptors, sizeof(D3D12Descriptor) * desc.NumDescriptors);
+  for(UINT i = 0; i < desc.NumDescriptors; i++)
     descriptors[i].Setup(this, i);
 }
 
diff --git a/renderdoc/driver/d3d12/d3d12_resources.h b/renderdoc/driver/d3d12/d3d12_resources.h
index 1758bdecf..5c8885360 100644
--- a/renderdoc/driver/d3d12/d3d12_resources.h
+++ b/renderdoc/driver/d3d12/d3d12_resources.h
@@ -402,7 +402,7 @@ public:
   };
 
   WrappedID3D12DescriptorHeap(ID3D12DescriptorHeap *real, WrappedID3D12Device *device,
-                              const D3D12_DESCRIPTOR_HEAP_DESC &desc);
+                              const D3D12_DESCRIPTOR_HEAP_DESC &desc, UINT UnpatchedNumDescriptors);
   virtual ~WrappedID3D12DescriptorHeap();
 
   D3D12Descriptor *GetDescriptors() { return descriptors; }