Recently installed updates and this cause an the Rapid Recovery Console page to get an XML error. This was caused by a bad update : KB338830 - Windows Server 2012
After uninstalling this update the console access was working as normal. Also note that during the time i was unable to login to the console my normally scheduled jobs still ran as per the schedule.
As you mentioned, this is an issue specific to Windows 2012 only. Newer Windows versions are not affected. Although your solution is valid (and provides short term relief) a simpler and better approach is upgrading the core software to RapidRecovery 22.214.171.124 which works with all current Windows 2012 updates.