diff --git a/Source/cmVisualStudio10TargetGenerator.cxx b/Source/cmVisualStudio10TargetGenerator.cxx
index a7822b215a..cd4326ffe1 100644
--- a/Source/cmVisualStudio10TargetGenerator.cxx
+++ b/Source/cmVisualStudio10TargetGenerator.cxx
@@ -2351,7 +2351,7 @@ void cmVisualStudio10TargetGenerator::WriteAllSources(Elem& e0)
           // Visual Studio versions prior to 2017 15.8 do not know about unity
           // builds, thus we exclude the files already part of unity sources.
           if (!si.Source->GetPropertyAsBool("SKIP_UNITY_BUILD_INCLUSION")) {
-            exclude_configs = si.Configs;
+            exclude_configs = all_configs;
           }
         }
       }