diff --git a/build/install.targets b/build/install.targets
index b43e8f7cd..818536fbb 100644
--- a/build/install.targets
+++ b/build/install.targets
@@ -10,7 +10,7 @@
   <Target
     Name="ComputeHeaderOutputs"
     Inputs="@(InstallHeader)"
-    Outputs="@(InstallHeader->'%(HeaderRoot)|%(RelativeDir)')"
+    Outputs="@(InstallHeader->'%(HeaderRoot)\%(RelativeDir)')"
     BeforeTargets="InstallHeaders"
     >
     <CalculateOutputDir