diff --git a/Source/Core/Core/MemoryWatcher.cpp b/Source/Core/Core/MemoryWatcher.cpp
index 4f92ae82e18d..2526ac134c01 100644
--- a/Source/Core/Core/MemoryWatcher.cpp
+++ b/Source/Core/Core/MemoryWatcher.cpp
@@ -139,6 +139,7 @@ void MemoryWatcher::Step()
       current_value = new_value;
       std::string message = ComposeMessage(address, new_value);
 #ifdef _WIN32
+      unsigned long m_written;
       if (m_pipe != INVALID_HANDLE_VALUE)
         WriteFile(m_pipe, message.c_str(), static_cast<DWORD>(message.size() + 1), &m_written,
                   nullptr);
diff --git a/Source/Core/Core/MemoryWatcher.h b/Source/Core/Core/MemoryWatcher.h
index 29b3a0bd6d19..c983b4289e7c 100644
--- a/Source/Core/Core/MemoryWatcher.h
+++ b/Source/Core/Core/MemoryWatcher.h
@@ -43,7 +43,6 @@ class MemoryWatcher final
 
 #ifdef _WIN32
   void* m_pipe;
-  unsigned long m_written;
 #else
   int m_fd;
   sockaddr_un m_addr;