diff --git a/web/public/locales/en/views/classificationModel.json b/web/public/locales/en/views/classificationModel.json
index 96bf0284b..a07114b5c 100644
--- a/web/public/locales/en/views/classificationModel.json
+++ b/web/public/locales/en/views/classificationModel.json
@@ -139,6 +139,7 @@
         "nameOnlyNumbers": "Model name cannot contain only numbers",
         "classRequired": "At least 1 class is required",
         "classesUnique": "Class names must be unique",
+        "noneNotAllowed": "The class 'none' is not allowed",
         "stateRequiresTwoClasses": "State models require at least 2 classes",
         "objectLabelRequired": "Please select an object label",
         "objectTypeRequired": "Please select a classification type"
diff --git a/web/src/components/classification/wizard/Step1NameAndDefine.tsx b/web/src/components/classification/wizard/Step1NameAndDefine.tsx
index d5ee430eb..a4cdc4867 100644
--- a/web/src/components/classification/wizard/Step1NameAndDefine.tsx
+++ b/web/src/components/classification/wizard/Step1NameAndDefine.tsx
@@ -94,7 +94,14 @@ export default function Step1NameAndDefine({
       objectLabel: z.string().optional(),
       objectType: z.enum(["sub_label", "attribute"]).optional(),
       classes: z
-        .array(z.string())
+        .array(
+          z
+            .string()
+            .refine(
+              (val) => val.trim().toLowerCase() !== "none",
+              t("wizard.step1.errors.noneNotAllowed"),
+            ),
+        )
         .min(1, t("wizard.step1.errors.classRequired"))
         .refine(
           (classes) => {
@@ -467,6 +474,7 @@ export default function Step1NameAndDefine({
                           )}
                         </div>
                       </FormControl>
+                      <FormMessage />
                     </FormItem>
                   )}
                 />