diff --git a/Source/cmQtAutoGenInitializer.cxx b/Source/cmQtAutoGenInitializer.cxx
index a2dc232dd7..4f6102a47f 100644
--- a/Source/cmQtAutoGenInitializer.cxx
+++ b/Source/cmQtAutoGenInitializer.cxx
@@ -1394,7 +1394,9 @@ bool cmQtAutoGenInitializer::InitAutogenTarget()
   if (this->Uic.Enabled) {
     for (auto const& file : this->Uic.UiHeaders) {
       this->AddGeneratedSource(file.first, this->Uic);
-      autogenByproducts.push_back(file.second);
+      if (this->GlobalGen && !GlobalGen->IsFastbuild()) {
+        autogenByproducts.push_back(file.second);
+      }
     }
   }