diff --git a/ide/vs2019/mimalloc-override.vcxproj b/ide/vs2019/mimalloc-override.vcxproj
index 5fa59569..5fb809c8 100644
--- a/ide/vs2019/mimalloc-override.vcxproj
+++ b/ide/vs2019/mimalloc-override.vcxproj
@@ -236,6 +236,7 @@
     <ClCompile Include="..\..\src\bitmap.c" />
     <ClCompile Include="..\..\src\heap.c" />
     <ClCompile Include="..\..\src\init.c" />
+    <ClCompile Include="..\..\src\prim\prim.c" />
     <ClCompile Include="..\..\src\region.c" />
     <ClCompile Include="..\..\src\options.c" />
     <ClCompile Include="..\..\src\os.c" />
diff --git a/ide/vs2019/mimalloc-override.vcxproj.filters b/ide/vs2019/mimalloc-override.vcxproj.filters
index c06fd1de..737e0600 100644
--- a/ide/vs2019/mimalloc-override.vcxproj.filters
+++ b/ide/vs2019/mimalloc-override.vcxproj.filters
@@ -49,6 +49,7 @@
     <ClCompile Include="..\..\src\bitmap.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\prim\prim.c" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="$(ProjectDir)..\..\include\mimalloc.h">
diff --git a/ide/vs2019/mimalloc.vcxproj b/ide/vs2019/mimalloc.vcxproj
index c12955c3..9e372ca4 100644
--- a/ide/vs2019/mimalloc.vcxproj
+++ b/ide/vs2019/mimalloc.vcxproj
@@ -225,6 +225,7 @@
     </ClCompile>
     <ClCompile Include="..\..\src\heap.c" />
     <ClCompile Include="..\..\src\init.c" />
+    <ClCompile Include="..\..\src\prim\prim.c" />
     <ClCompile Include="..\..\src\region.c" />
     <ClCompile Include="..\..\src\options.c" />
     <ClCompile Include="..\..\src\page-queue.c">
diff --git a/ide/vs2019/mimalloc.vcxproj.filters b/ide/vs2019/mimalloc.vcxproj.filters
index 4cd0eb2e..5ab88914 100644
--- a/ide/vs2019/mimalloc.vcxproj.filters
+++ b/ide/vs2019/mimalloc.vcxproj.filters
@@ -52,6 +52,9 @@
     <ClCompile Include="..\..\src\bitmap.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\prim\prim.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="$(ProjectDir)..\..\include\mimalloc.h">