diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index b9de4d8aa..6c95ea805 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -828,6 +828,7 @@ void cmGlobalGenerator::Configure()
   this->LocalGenerators.clear();
   this->TargetDependencies.clear();
   this->TotalTargets.clear();
+  this->ImportedTargets.clear();
   this->LocalGeneratorToTargetMap.clear();
   this->ProjectMap.clear();
   this->RuleHashes.clear();