diff --git a/sickbeard/providers/xthor.py b/sickbeard/providers/xthor.py
index 043e5e5da06f3fcddd0c5af1861789cc21c833a3..22271f4f4fa288329c322b5ba717423d5efae370 100644
--- a/sickbeard/providers/xthor.py
+++ b/sickbeard/providers/xthor.py
@@ -51,7 +51,7 @@ class XthorProvider(TorrentProvider):  # pylint: disable=too-many-instance-attri
         self.username = None
         self.password = None
         self.freeleech = None
-
+        self.proper_strings = ['PROPER']
         self.cache = XthorCache(self)
 
     def login(self):