Not long after Apple fixed one 1970-related iPhone glitch, a second one appears to be at work. A number of iPhone and iPad owners are tweeting screengrabs of ghost emails arriving from 1st January 1970. The emails have no sender, subject or content, and cannot be deleted, reports the Telegraph.

The good news is that this glitch doesn’t do any harm. The date is simply the Unix equivalent of zero, so the iOS Mail app would default to this if for some reason the correct date and time were missing, as one Reddit user explained …

The way it works is that the date is stored as a continuously increasing collection of over a billion seconds (ignores timezone conversions, easy for computers to handle in binary). This is typically called Unix time or Epoch time. For example, the current time right now (in this format) is about 1.45 billion. Like I said, it’s easy for a computer to handle this number to store the date in binary, especially on a 64-bit device. Well, if it’s 1.45 billion right now, what’s 0? The answer is January 1st, 1970, at midnight.

Most (but not all) of those affected seem to experience the issue when changing timezone.

Quitting the email app and then resetting the device (holding down the power and Home buttons until the Apple logo appears) seems to remove the ghost emails and stop them reappearing.