diff --git a/packages/strapi-admin/admin/src/containers/Admin/Wrapper.js b/packages/strapi-admin/admin/src/containers/Admin/Wrapper.js
index 327b2dd0e7..dd26540a6d 100644
--- a/packages/strapi-admin/admin/src/containers/Admin/Wrapper.js
+++ b/packages/strapi-admin/admin/src/containers/Admin/Wrapper.js
@@ -9,8 +9,18 @@ const Wrapper = styled.div`
   }
 
   .adminPageRightWrapper {
-    width: calc(100% - #{$left-menu-width});
+    width: ${props => `calc(100% - ${props.theme.main.sizes.leftMenu.width})`};
   }
 `;
 
+Wrapper.defaultProps = {
+  theme: {
+    main: {
+      sizes: {
+        leftMenu: {},
+      },
+    },
+  },
+};
+
 export default Wrapper;
diff --git a/packages/strapi-plugin-content-type-builder/admin/src/containers/ModelForm/index.js b/packages/strapi-plugin-content-type-builder/admin/src/containers/ModelForm/index.js
index 50df0bfe5b..3c2374fa98 100644
--- a/packages/strapi-plugin-content-type-builder/admin/src/containers/ModelForm/index.js
+++ b/packages/strapi-plugin-content-type-builder/admin/src/containers/ModelForm/index.js
@@ -31,6 +31,7 @@ import IconGroup from '../../assets/icons/icon_type_groups.png';
 import forms from './forms.json';
 
 const NAVLINKS = [{ id: 'base' }, { id: 'advanced' }];
+const RESERVED_NAMES = ['admin', 'series', 'file'];
 
 class ModelForm extends React.Component {
   // eslint-disable-line react/prefer-stateless-function
@@ -98,6 +99,12 @@ class ModelForm extends React.Component {
     );
     let formErrors = {};
 
+    if (RESERVED_NAMES.includes(modifiedData.name)) {
+      formErrors = {
+        name: [{ id: `${pluginId}.error.contentTypeName.reserved-name` }],
+      };
+    }
+
     if (alreadyTakenContentTypeNames.includes(modifiedData.name)) {
       formErrors = {
         name: [{ id: `${pluginId}.error.contentTypeName.taken` }],
diff --git a/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json b/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json
index 09ea73702a..10061f97f5 100644
--- a/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json
+++ b/packages/strapi-plugin-content-type-builder/admin/src/translations/en.json
@@ -32,6 +32,7 @@
   "error.attribute.sameKeyAndName": "Can't be equal",
   "error.attribute.taken": "This field name already exists",
   "error.contentTypeName.taken": "This name already exists",
+  "error.contentTypeName.reserved-name": "This name cannot be used in your project as it might break other functionnalities",
   "error.validation.max": "The value is too high.",
   "error.validation.maxLength": "The value is too long.",
   "error.validation.min": "The value is too low.",
diff --git a/packages/strapi-plugin-content-type-builder/admin/src/translations/fr.json b/packages/strapi-plugin-content-type-builder/admin/src/translations/fr.json
index 7824551f5e..c17f82422e 100644
--- a/packages/strapi-plugin-content-type-builder/admin/src/translations/fr.json
+++ b/packages/strapi-plugin-content-type-builder/admin/src/translations/fr.json
@@ -31,6 +31,7 @@
   "error.attribute.sameKeyAndName": "Ne peuvent pas être égaux",
   "error.attribute.taken": "Ce champ existe déjà",
   "error.contentTypeName.taken": "Ce nom existe déjà",
+  "error.contentTypeName.reserved-name": "Ce nom ne peut être utilisé",
   "error.validation.max": "La valeur est trop grande.",
   "error.validation.maxLength": "La valeur est trop longue.",
   "error.validation.min": "La valeur est trop basse.",