I bought a Samsung Galaxy S3 last week and found that straight out of the box the S Planner calendar app would throw the error ‘Unfortunately S.Planner has stopped.’
I updated the Samsung software and rebooted the device but no resolve, finally I managed to fix it with the following process:
From the Settings menu select ‘Applications Manager’, now click on the ‘All’ option up the top right. Scroll down and find S Planner and click on it. In the App Info screen click the ‘Clear Cache’ button and then click the ‘Disable button’, now click the ‘Force Stop’ button, and finally now click the ‘Enable’ button and your S Planner app should be working again.