diff --git a/compiler/extensions/cpp/src/zserio/extension/cpp/CppExtension.java b/compiler/extensions/cpp/src/zserio/extension/cpp/CppExtension.java
index e8bdb612d..c47526c59 100644
--- a/compiler/extensions/cpp/src/zserio/extension/cpp/CppExtension.java
+++ b/compiler/extensions/cpp/src/zserio/extension/cpp/CppExtension.java
@@ -54,8 +54,6 @@ public boolean isEnabled(ExtensionParameters parameters)
     @Override
     public void check(Root rootNode, ExtensionParameters parameters) throws ZserioExtensionException
     {
-        CppExtensionParameters.check(parameters);
-
         final CompatibilityChecker compatibilityChecker = new CompatibilityChecker();
         rootNode.walk(compatibilityChecker);
 
@@ -70,6 +68,9 @@ public void check(Root rootNode, ExtensionParameters parameters) throws ZserioEx
     @Override
     public void process(Root rootNode, ExtensionParameters parameters) throws ZserioExtensionException
     {
+        // this check should be here not in check() method to avoid reporting error if extension is not called
+        CppExtensionParameters.check(parameters);
+
         final OutputFileManager outputFileManager = new OutputFileManager(parameters);
         final CppExtensionParameters cppParameters = new CppExtensionParameters(parameters);