Mac OS X 10.7.5 Keychain hangs forever

I always get this problem when using Remote Desktop. Even though race_carr's answer to reset the keychain will likely work, I think the process is too destructive. What I just did was go into keychain and clean up the login->certificates section by removing duplicate, untrusted, and old certificates. That fixed the freezing problem.

I would recommend resetting to a new/default keychain and see if that resolves the issue. Keep in mind that any stored passwords, keys, secure notes, or certificates will be deleted when you do this.

In Keychain Access.app under Preferences choose "Reset My Default Keychain" and then restart (for good measure). See also: Reset Mac OS X Keychain.