Ipad calendar (the native version) opened once after upgrade and crashed. Now it can't even be launched anymore. I tried restart, reboot, stopped iCloud, restarted, stopped calendar in settings and restarted, synced, backed up etc etc did just about everything except a complete reinstallation. I have been reading so many horror stories about problems with the upgrade to OS5 that I'm just not sure this is the way to go. I'm disappointed as the upgrade brought so much upheaval. My Ipad's only a few months old and was fine until the upgrade. Then the error message started each time I synced or logged on to Itunes. Error, upgrade was 'interrupted'. Press continue to complete... then 'error (-50), now this issue. This Ipad is my first Apple item and I'm not convinced it is all that it pretends to be. I was told by Apple agents that Apple was sooo much better than Microsoft but as yet, I can't say my Apple product is any better than all the other technologies nor is Apple any more helpful. Any ideas on what might cause the Calendar malfunction and how to deal with it? Many thanks in advance.