Upgrade to WordPress 3.5.2 – Error: upgrade.php?_wp_http_referer=/wp-admin/

I have upgraded to WP 3.5.2 When it finished, I can see my website, but I cann’t login to admin area (www.xxxxxxxxxx.com/wp-admin). It redirects me to http://xxxxxxxxx.com/wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F

While this solution was for an earlier version of WordPress it worked perfectly in this case for me. I suspect this can/will happen with any future version of WordPress because it’s an error that happens, resulting in the in-app update process download being corrupted and missed the required upgrade.php.

SOLUTION:
I found solution from chowsir (http://wordpress.org/support/profile/chowsir) in his response to the same issue on a previous version of WordPress here: http://wordpress.org/support/topic/upgrade-to-34

Reposted from chowsir:

If you are getting the yoursite.com/wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F error, this worked for me: Navigate via FTP to your installation. Check to see if the upgrade.php file is there. If not, download WordPress 3.4.2 from http://www.wordpress.org. Unzip the download and navigate to the wp-admin folder. Locate the upgrade.php file and FTP it to your installation. Somehow the in-app update process download was corrupted and missed the required upgrade.php which the redirect points to after the update. Good luck! ~chowsir

Thank you chowsir very much for this solution and the reason why this error occurs. I’m sure many WordPress users will find your solution helpful and make them aware of this installation error and how to solve it when it happens again.

I hope this helps everyone that experiences this error upgrade.php?_wp_http_referer=%2Fwp-admin%2F on current WordPress Installs.