diff --git a/libs/freetdm/msvc/freetdm.2008.vcproj b/libs/freetdm/msvc/freetdm.2008.vcproj
index 2619f23d74..c3a0d7ad08 100644
--- a/libs/freetdm/msvc/freetdm.2008.vcproj
+++ b/libs/freetdm/msvc/freetdm.2008.vcproj
@@ -122,7 +122,7 @@
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				AdditionalIncludeDirectories="../src/include;../src/include/private;../src/isdn/include"
-				PreprocessorDefinitions="WIN32;_DEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS"
+				PreprocessorDefinitions="WIN32;_DEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0501"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="3"
@@ -198,7 +198,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				AdditionalIncludeDirectories="../src/include;../src/include/private;../src/isdn/include"
-				PreprocessorDefinitions="WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS"
+				PreprocessorDefinitions="WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0501"
 				RuntimeLibrary="2"
 				DisableLanguageExtensions="false"
 				RuntimeTypeInfo="false"
@@ -271,7 +271,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				AdditionalIncludeDirectories="../src/include;../src/include/private;../src/isdn/include"
-				PreprocessorDefinitions="WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS"
+				PreprocessorDefinitions="WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0501"
 				RuntimeLibrary="2"
 				DisableLanguageExtensions="false"
 				RuntimeTypeInfo="false"
diff --git a/libs/freetdm/msvc/freetdm.2010.vcxproj b/libs/freetdm/msvc/freetdm.2010.vcxproj
index aecb9ef79c..7b95612031 100644
--- a/libs/freetdm/msvc/freetdm.2010.vcxproj
+++ b/libs/freetdm/msvc/freetdm.2010.vcxproj
@@ -89,7 +89,7 @@
     <ClCompile>
       <Optimization>Disabled</Optimization>
       <AdditionalIncludeDirectories>../src/include;../src/include/private;../src/isdn/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0502;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <MinimalRebuild>true</MinimalRebuild>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
@@ -112,7 +112,7 @@
     </BuildLog>
     <ClCompile>
       <AdditionalIncludeDirectories>../src/include;../src/include/private;../src/isdn/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0502;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <RuntimeTypeInfo>false</RuntimeTypeInfo>
@@ -134,7 +134,7 @@
     <ClCompile>
       <Optimization>Disabled</Optimization>
       <AdditionalIncludeDirectories>../src/include;../src/include/private;../src/isdn/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0502;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <MinimalRebuild>true</MinimalRebuild>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
@@ -161,7 +161,7 @@
     </Midl>
     <ClCompile>
       <AdditionalIncludeDirectories>../src/include;../src/include/private;../src/isdn/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;_CRT_SECURE_NO_WARNINGS;FREETDM_EXPORTS;TELETONE_EXPORTS;_WIN32_WINNT=0x0502;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <RuntimeTypeInfo>false</RuntimeTypeInfo>
@@ -222,4 +222,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
\ No newline at end of file
+</Project>