fix TypeError: season_folders_format = ""

sickbeard/config.py

@@ -306,13 +306,18 @@ class ConfigMigrator():
 
             old_season_format = check_setting_str(self.config_obj, 'General', 'season_folders_format', 'Season %02d')
 
+            if old_season_format:
+                try:
                     new_season_format = old_season_format % 9
                     new_season_format = new_season_format.replace('09', '%0S')
                     new_season_format = new_season_format.replace('9', '%S')
-            logger.log(u"Changed season folder format from "+old_season_format+" to "+new_season_format+", prepending it to your naming config")
 
+                    logger.log(u"Changed season folder format from " + old_season_format + " to " + new_season_format + ", prepending it to your naming config")
                     sickbeard.NAMING_PATTERN = new_season_format + os.sep + sickbeard.NAMING_PATTERN
 
+                except (TypeError, ValueError):
+                    logger.log(u"Can't change " + old_season_format + " to new season format", logger.ERROR)
+
         # if no shows had it on then don't flatten any shows and don't put season folders in the config
         else: