Apple has re-posted the Mac OS X 10.6.5 update, which it pulled yesterday. Mac OS X 10.6.5 was released last week for both Snow Leopard and Snow Leopard Server users.
Some who installed the update before it disappeared reported issues on the Apple Discussions forums, saying, for example, the update broke Lightweight Directory Access Protocol and Domain Name System functionality, while another said they had a problem with external drives.
The update presumably fixes these issues. It also reportedly fixes a memory aliasing issue in Dovecot’s handling of user names.