diff --git a/src/map/map-server.vcxproj.filters b/src/map/map-server.vcxproj.filters
index 4bf3bcd07f..ab9ab51dc1 100644
--- a/src/map/map-server.vcxproj.filters
+++ b/src/map/map-server.vcxproj.filters
@@ -152,6 +152,9 @@
     <ClInclude Include="item_upgrade.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="item_synthesis.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="achievement.cpp">
@@ -280,5 +283,8 @@
     <ClCompile Include="item_upgrade.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="item_synthesis.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
-</Project>
+</Project>
\ No newline at end of file