diff --git a/renderdoc/driver/shaders/dxbc/dxbc_container.cpp b/renderdoc/driver/shaders/dxbc/dxbc_container.cpp
index 5b5753139..b5b9e34a1 100644
--- a/renderdoc/driver/shaders/dxbc/dxbc_container.cpp
+++ b/renderdoc/driver/shaders/dxbc/dxbc_container.cpp
@@ -934,7 +934,7 @@ bytebuf DXBCContainer::MakeContainerForChunk(uint32_t fourcc, const byte *chunk,
   memcpy(write, &partHeader, sizeof(partHeader));
   write += sizeof(partHeader);
 
-  memcpy(write, chunk, chunkSize);
+  memcpy(write, chunk, (size_t)chunkSize);
 
   HashContainer(ret.data(), ret.size());