Another issue doing the rounds...
Many have resorted to deleting photos, videos and other files in order to free up space for the new version of Apple's mobile operating system, iOS8, which requires up to 5.8GB of storage.
David Price, online editor at Macworld UK, told the BBC the issues were not "really a surprise".
"There's always a rush on the servers on launch day, some delays, and usually some teething problems," he said.
"That's why we always recommend that people wait a day or two before updating."