After installing an update to WordPress I received the error:
“Briefly unavailable for scheduled maintenance. Check back in a minute.”
I was unsure if this was down to my hosts servers being temporarily down, going down during the update or if WordPress had simply failed to update whatever it was updating. Turns out it was the latter and it’s really easy to fix, first log on to your ftp, file manager or whatever for your hosting and browse to your wordpress install, in the root of this there should be a .maintenance file, just delete this and everything should be back to normal. Once back in the WordPress dashboard you may be asked to reinstall whatever failed however sometimes it will have completed the install and just not managed to delete this file.