Communicator 2007 R2 Client will not Sign in after applying update

I deployed Windows Updates to our domain last night and our communicator clients will not connect. The Update i applied was KB 2028888. The error that i am seeing is:

Cannot sign in to Communicator. You may have entered your sign-in address, user name, or password incorrectly, or the authentication service may be incompatible with this version of hte program. If your sign-in information is correct and hte problem persists, please contact your system administrator.

Is there something i would need to do on the OCS serve side of things to enable this new update?

Should i try and decline the updates (only on 10% of computers right now). ?

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Three suggestions:

- Can you restore the PCs before the update?

- Or totally uninstall/reinstall client.

- Or, do not install and wait for newest Communicator.  I'm beta testing it now and should be out shortly.  It will have a new name, but offer increased functionality and stability.
RavenIndAuthor Commented:
The issue was a Group Policy that was changed over the weekend to allow for Kerberos security. Once the GPO was removed everything now works. I will have to do some further research on this to figure out why it wasn't working with Kerberos enabled.

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