diff --git a/renderdoc/core/resource_manager.h b/renderdoc/core/resource_manager.h
index 6c2aaf07e..a3a540768 100644
--- a/renderdoc/core/resource_manager.h
+++ b/renderdoc/core/resource_manager.h
@@ -876,6 +876,8 @@ void ResourceManager<WrappedResourceType, RealResourceType, RecordType>::InsertR
 template<typename WrappedResourceType, typename RealResourceType, typename RecordType>
 void ResourceManager<WrappedResourceType, RealResourceType, RecordType>::PrepareInitialContents()
 {
+	SCOPED_LOCK(m_Lock);
+
 	for(auto it=m_DirtyResources.begin(); it != m_DirtyResources.end(); ++it)
 	{
 		ResourceId id = *it;