diff --git a/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp b/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
index 028613ebad6..6cc479ccd4e 100644
--- a/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
+++ b/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
@@ -94,9 +94,6 @@ ClangEditorDocumentProcessor::ClangEditorDocumentProcessor(
     connect(&m_builtinProcessor, &CppTools::BuiltinEditorDocumentProcessor::semanticInfoUpdated,
             this, &ClangEditorDocumentProcessor::semanticInfoUpdated);
 
-    connect(CppTools::CppModelManager::instance(), &CppTools::CppModelManager::projectPartsRemoved,
-            this, &ClangEditorDocumentProcessor::onProjectPartsRemoved);
-
     m_semanticHighlighter.setHighlightingRunner(
         [this]() -> QFuture<TextEditor::HighlightingResult> {
             const int firstLine = 1;
@@ -184,6 +181,11 @@ CppTools::ProjectPart::Ptr ClangEditorDocumentProcessor::projectPart() const
     return m_projectPart;
 }
 
+void ClangEditorDocumentProcessor::clearProjectPart()
+{
+    m_projectPart.clear();
+}
+
 void ClangEditorDocumentProcessor::updateCodeWarnings(const QVector<ClangBackEnd::DiagnosticContainer> &diagnostics,
                                                       uint documentRevision)
 {
@@ -250,12 +252,6 @@ void ClangEditorDocumentProcessor::onParserFinished()
     updateProjectPartAndTranslationUnitForEditor();
 }
 
-void ClangEditorDocumentProcessor::onProjectPartsRemoved(const QStringList &projectPartIds)
-{
-    if (m_projectPart && projectPartIds.contains(m_projectPart->id()))
-        m_projectPart.clear();
-}
-
 void ClangEditorDocumentProcessor::updateTranslationUnitForEditor(CppTools::ProjectPart &projectPart)
 {
     QTC_ASSERT(m_modelManagerSupport, return);
diff --git a/src/plugins/clangcodemodel/clangeditordocumentprocessor.h b/src/plugins/clangcodemodel/clangeditordocumentprocessor.h
index e7d93a42286..26c156a2652 100644
--- a/src/plugins/clangcodemodel/clangeditordocumentprocessor.h
+++ b/src/plugins/clangcodemodel/clangeditordocumentprocessor.h
@@ -70,6 +70,7 @@ public:
 
     bool hasProjectPart() const;
     CppTools::ProjectPart::Ptr projectPart() const;
+    void clearProjectPart();
 
     void updateCodeWarnings(const QVector<ClangBackEnd::DiagnosticContainer> &diagnostics,
                             uint documentRevision);
@@ -82,7 +83,6 @@ public:
 
 private slots:
     void onParserFinished();
-    void onProjectPartsRemoved(const QStringList &projectPartIds);
 
 private:
     void updateProjectPartAndTranslationUnitForEditor();
diff --git a/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp b/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp
index dee58c99c4b..12f7f5b5119 100644
--- a/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp
+++ b/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp
@@ -271,8 +271,49 @@ void ModelManagerSupportClang::onProjectPartsUpdated(ProjectExplorer::Project *p
 
 void ModelManagerSupportClang::onProjectPartsRemoved(const QStringList &projectPartIds)
 {
-    if (!projectPartIds.isEmpty())
+    if (!projectPartIds.isEmpty()) {
+        unregisterTranslationUnitsWithProjectParts(projectPartIds);
         m_ipcCommunicator.unregisterProjectPartsForEditor(projectPartIds);
+    }
+}
+
+static QVector<ClangEditorDocumentProcessor *>
+clangProcessorsWithProjectParts(const QStringList &projectPartIds)
+{
+    QVector<ClangEditorDocumentProcessor *> result;
+
+    foreach (auto *editorDocument, cppModelManager()->cppEditorDocuments()) {
+        auto *processor = editorDocument->processor();
+        auto *clangProcessor = qobject_cast<ClangEditorDocumentProcessor *>(processor);
+        if (clangProcessor && clangProcessor->hasProjectPart()) {
+            if (projectPartIds.contains(clangProcessor->projectPart()->id()))
+                result.append(clangProcessor);
+        }
+    }
+
+    return result;
+}
+
+static QVector<ClangBackEnd::FileContainer>
+processorToFileContainer(ClangEditorDocumentProcessor *processor)
+{
+    QTC_ASSERT(processor, return QVector<ClangBackEnd::FileContainer>());
+
+    const QString filePath = processor->baseTextDocument()->filePath().toString();
+    const QString projectPartId = processor->projectPart()->id();
+
+    return {ClangBackEnd::FileContainer(filePath, projectPartId)};
+}
+
+void ModelManagerSupportClang::unregisterTranslationUnitsWithProjectParts(
+        const QStringList &projectPartIds)
+{
+    const auto processors = clangProcessorsWithProjectParts(projectPartIds);
+    foreach (ClangEditorDocumentProcessor *processor, processors) {
+        m_ipcCommunicator.unregisterTranslationUnitsForEditor(processorToFileContainer(processor));
+        processor->clearProjectPart();
+        processor->run();
+    }
 }
 
 #ifdef QT_TESTLIB_LIB
diff --git a/src/plugins/clangcodemodel/clangmodelmanagersupport.h b/src/plugins/clangcodemodel/clangmodelmanagersupport.h
index 057429c750d..b433f4c0ecf 100644
--- a/src/plugins/clangcodemodel/clangmodelmanagersupport.h
+++ b/src/plugins/clangcodemodel/clangmodelmanagersupport.h
@@ -89,6 +89,8 @@ private:
     void onProjectPartsUpdated(ProjectExplorer::Project *project);
     void onProjectPartsRemoved(const QStringList &projectPartIds);
 
+    void unregisterTranslationUnitsWithProjectParts(const QStringList &projectPartIds);
+
     void connectTextDocumentToTranslationUnit(TextEditor::TextDocument *textDocument);
     void connectTextDocumentToUnsavedFiles(TextEditor::TextDocument *textDocument);
     void connectToWidgetsMarkContextMenuRequested(QWidget *editorWidget);
diff --git a/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp b/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp
index c89bb6bf43c..46046d6d72c 100644
--- a/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp
+++ b/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp
@@ -1010,6 +1010,7 @@ void ClangCodeCompletionTest::testChangingProjectDependentCompletion()
     } // Project closed
 
     // Check again completion without project
+    openEditor.waitUntilProjectPartChanged(QLatin1String(""));
     proposal = completionResults(openEditor.editor());
     QVERIFY(hasItem(proposal, "noProjectConfigurationDetected"));
 }