When trying to view another person's calendar in Outlook 2013 and hash marks are present, this indicates the free/busy information is not displaying correct or the information is not available. This can occur if the user has no calendared items during the date range that is published to the server. In order to view or set the date range that is published to the server, please perform the command line switch /cleanfreebusy. For more information on the Outlook 2013 command line switches, see the below link.

Command Line Switches