If you happen to run your own WordPress website for blogging, news, or whatever, no doubt at some point you've run into this error message while trying to update your plugins / themes / installation itself. Often times it's just due to your server hiccuping; maybe the memory ran low for a minute, or some other minor issue. The worst part is that usually that message will get "stuck" there, even though you've successfully updated everything later!
Here's how to fix the problem.
Without getting into the techy details, there's a timeout involved behind the scenes, so just wait a bit, then try again.
After doing this however many number of times is necessary to complete the updates you'll probably still get the "An automated WordPress update has failed to complete - please attempt the update again now." error message, and even though going to your updates page says there are no more updates, it still hangs out up top on your screen.
Fortunately, there's a very simple fix, and it's completely safe to do.
That's it! The "An automated WordPress update has failed to complete - please attempt the update again now." message will be gone the next time you refresh the page on your WordPress site.