We’ve been upgrading to the latest update of WordPress 3.3.2 which features some security updates and have discovered a minor annoyance in that the upgrade can fail and reports on the dashboard :
Downloading update from http://wordpress.org/wordpress-3.3.2-partial-1.zip…Unpacking the update…Could not copy files.Installation Failed
A quick analysis showed that having the following setting in wp-config.php causes the failure :
If you comment this out from wp-config.php temporarily, you’ll be able to successfully upgrade and then re-enable this setting.
As with any upgrade, we recommend you backup your site first !