I have a wordpress installation running as multisite. The automatic update fails with this regardless of file ownership and permissions:
Downloading update from http://wordpress.org/wordpress-3.5-new-bundled.zip… Unpacking the update… Could not copy files. Installation Failed
So I tried the manual route, following the instructions at http://codex.wordpress.org/Updating_WordPress#Manual_Update. And when I go back into /wp-admin, it is still telling me to upgrade to 3.5.
I've double-checked that the files were all copied from the latest.tar.gz file per the manual upgrade instructions. I'm at a loss.