WordPress automatic update goes wrong with 404 and URL of wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F
I haven’t entered any post lately and when I jumped on the admin to enter one I got the nag screen about updating WordPress. Foolishly without thinking I just did the automatic update. I normally go through the GoDaddy upgrade script and have not had problems with it but launching this update from the admin I could not enter login to the admin. I kept getting a 404 error page and the URL was wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F.
The actual blog did not go done and seem to survive the upgrade. It was only the admin that was not accessible.
Doing some looking around on the web for the simplest way to fix this I saw post about doing a manual install over the update. A number of other suggestions that seemed to much effort. I got a hint from one of the post indicating copying files over similar to a manual install.
Since the page not found was coming from the wp-admin directory I took a gamble and downloaded WordPress 3.4.2 to my local machine. I then uploaded only the wp-admin over my upgraded site. Presto error page is gone.
Upon doing this when logging into the admin page I was prompted to upgrade the WP database. I did and all is well.