diff --git a/Bloxstrap/Resources/Strings.Designer.cs b/Bloxstrap/Resources/Strings.Designer.cs
index f05872b..353e05e 100644
--- a/Bloxstrap/Resources/Strings.Designer.cs
+++ b/Bloxstrap/Resources/Strings.Designer.cs
@@ -1153,6 +1153,25 @@ namespace Bloxstrap.Resources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to No custom theme selected.
+        /// </summary>
+        public static string CustomTheme_Errors_NoThemeSelected {
+            get {
+                return ResourceManager.GetString("CustomTheme.Errors.NoThemeSelected", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Failed to setup custom bootstrapper: {0}.
+        ///Defaulting to Fluent..
+        /// </summary>
+        public static string CustomTheme_Errors_SetupFailed {
+            get {
+                return ResourceManager.GetString("CustomTheme.Errors.SetupFailed", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Theme XML root is not {0}.
         /// </summary>
diff --git a/Bloxstrap/Resources/Strings.resx b/Bloxstrap/Resources/Strings.resx
index 0d14ee0..0f45f53 100644
--- a/Bloxstrap/Resources/Strings.resx
+++ b/Bloxstrap/Resources/Strings.resx
@@ -1423,4 +1423,11 @@ Please close any applications that may be using Roblox's files, and relaunch.</v
   <data name="CustomTheme.Add.Errors.ZipInvalidData" xml:space="preserve">
     <value>Invalid or corrupted ZIP file</value>
   </data>
+  <data name="CustomTheme.Errors.NoThemeSelected" xml:space="preserve">
+    <value>No custom theme selected</value>
+  </data>
+  <data name="CustomTheme.Errors.SetupFailed" xml:space="preserve">
+    <value>Failed to setup custom bootstrapper: {0}.
+Defaulting to Fluent.</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/Bloxstrap/UI/Frontend.cs b/Bloxstrap/UI/Frontend.cs
index 8be7e1e..318a45f 100644
--- a/Bloxstrap/UI/Frontend.cs
+++ b/Bloxstrap/UI/Frontend.cs
@@ -67,7 +67,7 @@ namespace Bloxstrap.UI
             try
             {
                 if (App.Settings.Prop.SelectedCustomTheme == null)
-                    throw new Exception("No custom theme selected");
+                    throw new CustomThemeException("CustomTheme.Errors.NoThemeSelected");
 
                 CustomDialog dialog = new CustomDialog();
                 dialog.ApplyCustomTheme(App.Settings.Prop.SelectedCustomTheme);
@@ -78,7 +78,7 @@ namespace Bloxstrap.UI
                 App.Logger.WriteException(LOG_IDENT, ex);
 
                 if (!App.LaunchSettings.QuietFlag.Active)
-                    Frontend.ShowMessageBox($"Failed to setup custom bootstrapper: {ex.Message}.\nDefaulting to Fluent.", MessageBoxImage.Error);
+                    ShowMessageBox(string.Format(Strings.CustomTheme_Errors_SetupFailed, ex.Message), MessageBoxImage.Error);
 
                 return GetBootstrapperDialog(BootstrapperStyle.FluentDialog);
             }