diff --git a/osu.Game/Online/API/RegistrationRequest.cs b/osu.Game/Online/API/RegistrationRequest.cs
index 6dc867481a..dfedaa30e0 100644
--- a/osu.Game/Online/API/RegistrationRequest.cs
+++ b/osu.Game/Online/API/RegistrationRequest.cs
@@ -1,17 +1,16 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
+using System;
 using Newtonsoft.Json;
 
 namespace osu.Game.Online.API
 {
     public class RegistrationRequest : OsuWebRequest
     {
-        internal string Username;
-        internal string Email;
-        internal string Password;
+        internal string Username = string.Empty;
+        internal string Email = string.Empty;
+        internal string Password = string.Empty;
 
         protected override void PrePerform()
         {
@@ -24,18 +23,18 @@ protected override void PrePerform()
 
         public class RegistrationRequestErrors
         {
-            public UserErrors User;
+            public UserErrors? User;
 
             public class UserErrors
             {
                 [JsonProperty("username")]
-                public string[] Username;
+                public string[] Username = Array.Empty<string>();
 
                 [JsonProperty("user_email")]
-                public string[] Email;
+                public string[] Email = Array.Empty<string>();
 
                 [JsonProperty("password")]
-                public string[] Password;
+                public string[] Password = Array.Empty<string>();
             }
         }
     }