diff --git a/lib/phast/server/UUID.inc.php b/lib/phast/server/UUID.inc.php
index e5fd205..e72103f 100644
--- a/lib/phast/server/UUID.inc.php
+++ b/lib/phast/server/UUID.inc.php
@@ -176,8 +176,11 @@
             return $result;
         }
 
-		public static function parse(string $value)
+		public static function parse(?string $value) : ?UUID
 		{
+			if ($value == null)
+				return null;
+			
 			$result = UUID::TryParseGuidWithDashes($value);
 			return $result->parsedGuid;
 		}