diff --git a/src/plugins/languageclient/client.cpp b/src/plugins/languageclient/client.cpp
index b45d8af37cb..e9ab9c5db4e 100644
--- a/src/plugins/languageclient/client.cpp
+++ b/src/plugins/languageclient/client.cpp
@@ -987,7 +987,8 @@ void Client::documentContentsChanged(TextEditor::TextDocument *document,
 {
     if (!d->m_openedDocument.contains(document) || !reachable())
         return;
-    d->m_diagnosticManager->disableDiagnostics(document);
+    if (d->m_diagnosticManager)
+        d->m_diagnosticManager->disableDiagnostics(document);
     const QString method(DidChangeTextDocumentNotification::methodName);
     TextDocumentSyncKind syncKind = d->m_serverCapabilities.textDocumentSyncKindHelper();
     if (Utils::optional<bool> registered = d->m_dynamicCapabilities.isRegistered(method)) {