diff --git a/.github/workflows/ZenLib_Checks.yml b/.github/workflows/ZenLib_Checks.yml
index 1ed58bc..563b1d7 100644
--- a/.github/workflows/ZenLib_Checks.yml
+++ b/.github/workflows/ZenLib_Checks.yml
@@ -9,6 +9,8 @@ jobs:
         os: [ubuntu-latest, macos-latest]
       fail-fast: false
     runs-on: ${{ matrix.os }}
+    env:
+      CXXFLAGS: -Werror
     steps:
       - name: Checkout
         uses: actions/checkout@v5
diff --git a/Project/MSVC2022/Library/ZenLib.vcxproj b/Project/MSVC2022/Library/ZenLib.vcxproj
index fdca87a..d4aaabc 100644
--- a/Project/MSVC2022/Library/ZenLib.vcxproj
+++ b/Project/MSVC2022/Library/ZenLib.vcxproj
@@ -162,6 +162,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">
@@ -174,6 +175,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">
@@ -186,6 +188,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64EC'">
@@ -198,6 +201,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
@@ -210,6 +214,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
@@ -224,6 +229,7 @@
       <ControlFlowGuard>Guard</ControlFlowGuard>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">
@@ -237,6 +243,7 @@
       <ControlFlowGuard>Guard</ControlFlowGuard>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
@@ -252,6 +259,7 @@
       <GuardSignedReturns>true</GuardSignedReturns>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64EC'">
@@ -267,6 +275,7 @@
       <GuardSignedReturns>true</GuardSignedReturns>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
@@ -281,6 +290,7 @@
       <GuardEHContMetadata>true</GuardEHContMetadata>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemGroup>
diff --git a/Project/MSVC2026/Library/ZenLib.vcxproj b/Project/MSVC2026/Library/ZenLib.vcxproj
index 211c8a6..f281ea4 100644
--- a/Project/MSVC2026/Library/ZenLib.vcxproj
+++ b/Project/MSVC2026/Library/ZenLib.vcxproj
@@ -162,6 +162,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM'">
@@ -174,6 +175,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">
@@ -186,6 +188,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64EC'">
@@ -198,6 +201,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
@@ -210,6 +214,7 @@
       <Optimization>Disabled</Optimization>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
@@ -224,6 +229,7 @@
       <ControlFlowGuard>Guard</ControlFlowGuard>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM'">
@@ -237,6 +243,7 @@
       <ControlFlowGuard>Guard</ControlFlowGuard>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
@@ -252,6 +259,7 @@
       <GuardSignedReturns>true</GuardSignedReturns>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64EC'">
@@ -267,6 +275,7 @@
       <GuardSignedReturns>true</GuardSignedReturns>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
@@ -281,6 +290,7 @@
       <GuardEHContMetadata>true</GuardEHContMetadata>
       <LanguageStandard>stdcpp20</LanguageStandard>
       <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemGroup>
diff --git a/Source/ZenLib/Conf.h b/Source/ZenLib/Conf.h
index 735aa33..c1980ba 100644
--- a/Source/ZenLib/Conf.h
+++ b/Source/ZenLib/Conf.h
@@ -173,11 +173,6 @@
     #pragma warning(disable:4786) // MSVC6 doesn't like typenames longer than 255 chars (which generates an enormous amount of warnings).
 #endif
 
-//MSVC2005 : "deprecated" warning (replacement functions are not in MinGW32 or Borland!)
-#if defined(_MSC_VER) && _MSC_VER >= 1400
-    #pragma warning(disable : 4996)
-#endif
-
 //***************************************************************************
 // (Without Namespace)
 //***************************************************************************
diff --git a/Source/ZenLib/Ztring.cpp b/Source/ZenLib/Ztring.cpp
index 87760bb..e1b80c8 100644
--- a/Source/ZenLib/Ztring.cpp
+++ b/Source/ZenLib/Ztring.cpp
@@ -49,6 +49,13 @@
 using namespace std;
 //---------------------------------------------------------------------------
 
+//MSVC2005 : "deprecated" warning (replacement functions are not in MinGW32 or Borland!)
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+    #pragma warning(disable : 4996)
+#endif
+
+//---------------------------------------------------------------------------
+
 namespace ZenLib
 {