I have a iPhone 3GS, and an iPad 1, both on iOS5. I use a PC running Windows 7 and the latest version of iTunes. I have Cloud backup enabled in iTunes for both the phone and the ipad. If I look at the cloud settings on both devices, Cloud backup is enabled there too. When I press 'Back Up Now' on either the phone or the ipad, it says 'estimating time remaining' but it has never once actually displayed a time, and it has never completed (or even started, as far as I can see) a backup. Eventually it says "There was a problem completing the backup. Please try again later". I wondered if it was having a problem because of the amount of data that needs backing up, so I went in to 'Manage Storage' on both devices and un-checked virtually every app, leaving just a few turned on, and a total size to be backed up of about 30mb. The plan is to turn all those apps back on when the backup actually works. I've tried leaving the phone and ipad plugged in to the mains, unplugged from the mains, locked, unlocked, I've tried leaving them plugged in all night with the PC on and itunes left running. I've basically ran out of ideas, yet still iCloud Backup doesn't work. In a separate issue (but possibly related), I've never been able to wi-fi synch with iTunes either. I'd really welcome any advice or suggestions from anyone who has had these problems and managed to overcome them.