diff --git a/atdna/CMakeLists.txt b/atdna/CMakeLists.txt
index af9b4a5..bc00f92 100644
--- a/atdna/CMakeLists.txt
+++ b/atdna/CMakeLists.txt
@@ -6,8 +6,10 @@ if(NOT CMAKE_CROSSCOMPILING)
 
 # Force this binary to Release flags (to make MSVC happy)
 if(MSVC)
-set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_RELEASE}")
-set(CMAKE_EXE_LINKER_FLAGS_DEBUG "${CMAKE_EXE_LINKER_FLAGS_RELEASE}")
+  set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_RELEASE}")
+  set(CMAKE_EXE_LINKER_FLAGS_DEBUG "${CMAKE_EXE_LINKER_FLAGS_RELEASE}")
+  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "/MD /O2 /Ob2 /DNDEBUG")
+  set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "-debug -incremental:no")
 endif()
 
 # Find dependencies
diff --git a/include/athena/FileWriter.hpp b/include/athena/FileWriter.hpp
index 907f970..f908b4c 100644
--- a/include/athena/FileWriter.hpp
+++ b/include/athena/FileWriter.hpp
@@ -60,8 +60,6 @@ private:
     std::string  m_filename;
 #endif
     HandleType   m_fileHandle;
-    atUint8      m_currentByte;
-    atUint64     m_bytePosition;
     bool         m_globalErr;
 };
 
diff --git a/src/aes.cpp b/src/aes.cpp
index 2fcfcba..998e623 100644
--- a/src/aes.cpp
+++ b/src/aes.cpp
@@ -7,6 +7,10 @@
 #include <cpuid.h>
 #endif
 
+#if __AES__ || (!defined(__clang__) && _MSC_VER >= 1800)
+#define _AES_NI 1
+#endif
+
 namespace athena
 {
 
@@ -467,7 +471,7 @@ void SoftwareAES::encrypt(const uint8_t* iv, const uint8_t* inbuf, uint8_t* outb
     }
 }
 
-#if __AES__ || _MSC_VER >= 1800
+#if _AES_NI
 
 #include <wmmintrin.h>
 
@@ -582,12 +586,13 @@ public:
     }
 };
 
+static int HAS_AES_NI = -1;
+
 #endif
 
-static int HAS_AES_NI = -1;
 std::unique_ptr<IAES> NewAES()
 {
-#if __AES__ || _MSC_VER >= 1800
+#if _AES_NI
     if (HAS_AES_NI == -1)
     {
 #if _MSC_VER
diff --git a/src/athena/FileWriterWin32.cpp b/src/athena/FileWriterWin32.cpp
index d5e0023..1dcfdb1 100644
--- a/src/athena/FileWriterWin32.cpp
+++ b/src/athena/FileWriterWin32.cpp
@@ -5,7 +5,6 @@ namespace athena::io
 {
 FileWriter::FileWriter(std::string_view filename, bool overwrite, bool globalErr)
     : m_fileHandle(0),
-      m_bytePosition(0),
       m_globalErr(globalErr)
 {
     m_filename = utility::utf8ToWide(filename);
@@ -14,7 +13,6 @@ FileWriter::FileWriter(std::string_view filename, bool overwrite, bool globalErr
 
 FileWriter::FileWriter(std::wstring_view filename, bool overwrite, bool globalErr)
     : m_fileHandle(0),
-      m_bytePosition(0),
       m_globalErr(globalErr)
 {
     m_filename = filename;