diff --git a/src/tools/clangbackend/ipcsource/clangcodemodelserver.cpp b/src/tools/clangbackend/ipcsource/clangcodemodelserver.cpp
index 62070b37b0b..3cbbd494453 100644
--- a/src/tools/clangbackend/ipcsource/clangcodemodelserver.cpp
+++ b/src/tools/clangbackend/ipcsource/clangcodemodelserver.cpp
@@ -55,6 +55,12 @@
 #include <QCoreApplication>
 #include <QDebug>
 
+static bool useSupportiveTranslationUnit()
+{
+    static bool use = !qEnvironmentVariableIntValue("QTC_CLANG_NO_SUPPORTIVE_TRANSLATIONUNIT");
+    return use;
+}
+
 namespace ClangBackEnd {
 
 ClangCodeModelServer::ClangCodeModelServer()
@@ -116,9 +122,7 @@ void ClangCodeModelServer::updateTranslationUnitsForEditor(const UpdateTranslati
             // we might block the translation unit for a completion request
             // that comes right after this message.
             updateDocumentAnnotationsTimer.start(0);
-            QTimer::singleShot(0, [this, updateDocuments](){
-                startInitializingSupportiveTranslationUnits(updateDocuments);
-            });
+            delayStartInitializingSupportiveTranslationUnits(updateDocuments);
         }
     } catch (const std::exception &exception) {
         qWarning() << "Error in ClangCodeModelServer::updateTranslationUnitsForEditor:" << exception.what();
@@ -329,6 +333,16 @@ void ClangCodeModelServer::processInitialJobsForDocuments(const std::vector<Docu
     }
 }
 
+void ClangCodeModelServer::delayStartInitializingSupportiveTranslationUnits(
+        const std::vector<Document> &documents)
+{
+    if (useSupportiveTranslationUnit()) {
+        QTimer::singleShot(0, [this, documents](){
+            startInitializingSupportiveTranslationUnits(documents);
+        });
+    }
+}
+
 void ClangCodeModelServer::startInitializingSupportiveTranslationUnits(
         const std::vector<Document> &documents)
 {
diff --git a/src/tools/clangbackend/ipcsource/clangcodemodelserver.h b/src/tools/clangbackend/ipcsource/clangcodemodelserver.h
index b03b4327faf..2622c01db69 100644
--- a/src/tools/clangbackend/ipcsource/clangcodemodelserver.h
+++ b/src/tools/clangbackend/ipcsource/clangcodemodelserver.h
@@ -72,6 +72,7 @@ private:
     void startDocumentAnnotationsTimerIfFileIsNotOpenAsDocument(const Utf8String &filePath);
 
     void processInitialJobsForDocuments(const std::vector<Document> &documents);
+    void delayStartInitializingSupportiveTranslationUnits(const std::vector<Document> &documents);
     void startInitializingSupportiveTranslationUnits(const std::vector<Document> &documents);
 
     void processJobsForDirtyAndVisibleDocuments();