diff --git a/module/PowerShellEditorServices/PowerShellEditorServices.psm1 b/module/PowerShellEditorServices/PowerShellEditorServices.psm1
index 5e4f38191..b19caa8bd 100644
--- a/module/PowerShellEditorServices/PowerShellEditorServices.psm1
+++ b/module/PowerShellEditorServices/PowerShellEditorServices.psm1
@@ -49,7 +49,7 @@ function Start-EditorServicesHost {
         [ValidateNotNullOrEmpty()]
         $LogPath,
 
-        [ValidateSet("Normal", "Verbose", "Error")]
+        [ValidateSet("Normal", "Verbose", "Error", "Diagnostic")]
         $LogLevel = "Normal",
 
         [switch]
diff --git a/module/Start-EditorServices.ps1 b/module/Start-EditorServices.ps1
index c5a402486..332016352 100644
--- a/module/Start-EditorServices.ps1
+++ b/module/Start-EditorServices.ps1
@@ -44,7 +44,7 @@ param(
     [ValidateNotNullOrEmpty()]
     $LogPath,
 
-    [ValidateSet("Normal", "Verbose", "Error")]
+    [ValidateSet("Normal", "Verbose", "Error","Diagnostic")]
     $LogLevel,
 
     [switch]
@@ -191,4 +191,4 @@ catch [System.Exception] {
     }
 
     Write-Error ("`r`nCaught error while waiting for EditorServicesHost to complete:`r`n" + $errorString)
-}
\ No newline at end of file
+}