Problem occurs when box goes into standby
The reported fix will only work until you place the box into standby mode which will then promptly bugger up again resulting in the 'please wait' message when you next power up and attempt to access the planner. Whilst the box is in this state any hard disk activity will fail meaning that all scheduled recordings will also fail.
The only fix for now is to disable the auto standby features, switch the box off at the wall for a minute or so, power it back up and keep hitting the Sky button until the menu comes up, check you can access the planner and then leave the box switched on - do NOT put the box into standby or allow the automatic standby feature to do so otherwise it will simply become borked again.