OS X fix: hang when connecting to a network service or apple partner

This is an obscure fix. If OS X hangs when connecting to a network service, consider deleting a keychain file:

Aperture (Part 3)

Ordering Prints from Apple did not work (I got a Connecting to Apple's Book & Print Ordering Server dialog with an endless progress bar). After a bit of googling I found an iPhoto tip to use the Keychain Access app to delete the keychain file for NetServices. The problem vanished instantly.

OS X has its share of obscure fixes: Delete cache. Delete preferences files. Try another user account. And now ... delete keychains. (Delete permissions is well known, but probably less useful than any of the above.