After upgrading to WordPress 3.5.2 I can't log in to the control panel anymore. Instead, I'm redirected to /wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F where I'm presented with a 'Database Update Required' message and an 'Update WordPress Database' button. When I click on the button the page reloads, runs for a couple of seconds, and then nothing happens. All I get is a screen with the WordPress logo at the top and nothing else. The URL of the page is /wp-admin/upgrade.php?step=1&backto=%2Fwp-admin%2F.
I've tried various things to resolve the issue, without luck:
- Wait for an hour to see if the problem goes away (the first page does say that "the update process may take a little while")
- Tried to click the button in four different browsers
- Checked the server's error log (no errors at the time of the upgrade)
- Restored the database (I made a backup before I started the upgrade)
- Renamed the folder of my theme
- Renamed the plugins folder
The only other solution I can think of is downgrading WordPress to an older version. Does anyone have a better idea please?
PS - While searching for a solution I noticed a similar query was closed as "too localized". However, I reckon this is an issue "generally applicable to the worldwide audience of the internet". I'm not the first person to come across this issue, nor do I think I'll be the last!