Fixed: Trying to add an author when root folders hadn't populated

(cherry picked from commit a6d0dddaf7fa51f334e32d4fd49486d06fb6ba65)

frontend/src/Components/Form/RootFolderSelectInputConnector.js

@@ -102,6 +102,27 @@ class RootFolderSelectInputConnector extends Component {
     }
   }
 
+  componentDidUpdate(prevProps) {
+    const {
+      name,
+      value,
+      values,
+      onChange
+    } = this.props;
+
+    if (prevProps.values === values) {
+      return;
+    }
+
+    if (!value && values.length && values.some((v) => !!v.key && v.key !== ADD_NEW_KEY)) {
+      const defaultValue = values[0];
+
+      if (defaultValue.key !== ADD_NEW_KEY) {
+        onChange({ name, value: defaultValue.key });
+      }
+    }
+  }
+
   //
   // Render
 

src/Readarr.Api.V1/Author/AuthorFolderAsRootFolderValidator.cs

@@ -30,7 +30,13 @@ namespace Readarr.Api.V1.Author
             }
 
             var rootFolderPath = context.PropertyValue.ToString();
-            var rootFolder = new DirectoryInfo(rootFolderPath).Name;
+
+            if (rootFolderPath.IsNullOrWhiteSpace())
+            {
+                return true;
+            }
+
+            var rootFolder = new DirectoryInfo(rootFolderPath!).Name;
             var author = authorResource.ToModel();
             var authorFolder = _fileNameBuilder.GetAuthorFolder(author);