diff --git a/YouTrack.Rest/Deserialization/Issue.cs b/YouTrack.Rest/Deserialization/Issue.cs
index c4efae4..82a5aad 100644
--- a/YouTrack.Rest/Deserialization/Issue.cs
+++ b/YouTrack.Rest/Deserialization/Issue.cs
@@ -86,7 +86,7 @@ public void MapTo(Rest.Issue issue, IConnection connection)
             issue.ProjectShortName = GetString("projectShortName");
             issue.ReporterName = GetString("reporterName");
             issue.State = GetString("state");
-            issue.Subsystem = GetString("subsystem");
+            issue.Subsystem = GetString("subsystem", "");
             issue.Summary = GetString("summary");
             issue.Type = GetString("Type");
             issue.Updated = GetDateTime("updated");
@@ -110,4 +110,4 @@ private void MapFields(IDictionary<string, IEnumerable<string>> fields)
             }
         }
     }
-}
\ No newline at end of file
+}