After I manually upgrade my Multisite installation WordPress to WordPress 3.4, there are no themes show up on page of /wp-admin/network/themes.php
Then I set up two new WordPress site with multisite and non-multisite installation respectively to do some tests, the problems are the same: no themes show up.
But the sites DO have a theme assigned, which is the theme in use before I do the upgrade.
Please give me some help! Thank you!