Apple's iCloud service has had its share of outages and issues, but the latest problem, while apparently limited to a subset of accounts, just might be the most frustrating yet for those affected. Starting on or around Sept. 18, some iCloud customers found that apps that use iCloud to sync data between devices could no longer do so -- they either would no longer sync or appeared to have lost their data completely. The apps otherwise functioned normally, but simply didn't show any saved information or could not update or sync existing info.