After initiating the auto-update of the WordPress core (say, from 3.1.0 to 3.1.1), the “Update WordPress” screen will begin displaying the status of each step, beginning with these messages:
*Downloading update from http://wordpress.org/wordpress-3.1.1.zip…
Unpacking the update…
Verifying the unpacked files…
Installing the latest version…
Couldn’t copy file…
Installation failed*
The status message that appears just before “Installation Failed” explains what WordPress thinks is the issue, but there are cases where things go wrong and no messages are displayed. In either case, the user can get locked out of the site. When this happens, trying to load any of your pages – admin, blog, login, etc. – gets you the nothing but the WordPress maintenance page:
*Briefly unavailable for scheduled maintenance.
Check back in a minute.*
Very frustrating, and very difficult to fix things when you can’t log in to Admin. Fortunately, you don’t need Admin to fix it and get back in. Just FTP your way to the root directory and delete the **.maintenance** file. The name begins with a dot, so if you don’t see it using your FTP program, try logging into your server’s control panel and using the file manager to find and delete.
Zdroj: „http://digwp.com/2011/04/wordpress-auto-updates/“:http://digwp.com/2011/04/wordpress-auto-updates/
