You know what I'm talking about. You have a spreadsheet on both your iPhone and your iPad, and you blithely update on either device and watch it instantly update to the other device. 99% of the time. Oh but that 1% drives you crazy. The other device senses the change, starts to update the spreadsheet, the progress bar slowly crawls to the end, but before it gets to the very end, it stops. For hours. It just stops but doesn't end. I know about the workarounds (rebooting device, creating a new blank spreadsheet to get it to sync again, emailing the spreadsheet from one device to the other), but I'm wondering what's going on behind the scene? It clearly knows a sync is necessary. It clearly starts to do that sync. It clearly runs into a problem that prevents it from completing that sync. What is that problem? What is it doing as it sits there unable to complete? Is it querying iCloud and not getting a response?