diff --git a/org.eclipse.scout.sdk.util/src/org/eclipse/scout/sdk/util/internal/typecache/HierarchyCache.java b/org.eclipse.scout.sdk.util/src/org/eclipse/scout/sdk/util/internal/typecache/HierarchyCache.java
index f66a325..161f0f9 100644
--- a/org.eclipse.scout.sdk.util/src/org/eclipse/scout/sdk/util/internal/typecache/HierarchyCache.java
+++ b/org.eclipse.scout.sdk.util/src/org/eclipse/scout/sdk/util/internal/typecache/HierarchyCache.java
@@ -128,6 +128,9 @@
 
   @Override
   public ITypeHierarchy getSupertypeHierarchy(IType type) {
+    if (!TypeUtility.exists(type)) {
+      return null;
+    }
     try {
       return new TypeHierarchy(type, type.newSupertypeHierarchy(null));
     }
diff --git a/org.eclipse.scout.sdk/src/org/eclipse/scout/sdk/internal/workspace/dto/formdata/CompositeFormDataTypeSourceBuilder.java b/org.eclipse.scout.sdk/src/org/eclipse/scout/sdk/internal/workspace/dto/formdata/CompositeFormDataTypeSourceBuilder.java
index d85431c..5faea82 100644
--- a/org.eclipse.scout.sdk/src/org/eclipse/scout/sdk/internal/workspace/dto/formdata/CompositeFormDataTypeSourceBuilder.java
+++ b/org.eclipse.scout.sdk/src/org/eclipse/scout/sdk/internal/workspace/dto/formdata/CompositeFormDataTypeSourceBuilder.java
@@ -78,7 +78,12 @@
             formDataTypeName = Signature.getSignatureSimpleName(formDataTypeSignature);
           }
 
-          IType superType = TypeUtility.getTypeBySignature(fieldAnnotation.getSuperTypeSignature());
+          String superTypeSignature = fieldAnnotation.getSuperTypeSignature();
+          IType superType = TypeUtility.getTypeBySignature(superTypeSignature);
+          if (!TypeUtility.exists(superType)) {
+            ScoutSdk.logWarning("Could not read DTO super type of field '" + formField.getFullyQualifiedName() + "'. '" + superTypeSignature + "' Could not be found. Field will be skipped.");
+            continue;
+          }
           ITypeHierarchy superTypeHierarchy = TypeUtility.getSupertypeHierarchy(superType);
           ITypeSourceBuilder fieldSourceBuilder = null;
           if (superTypeHierarchy != null && superTypeHierarchy.contains(TypeUtility.getType(IRuntimeClasses.AbstractTableFieldData))) {