A User ID attribute value is already being used by another valid user in the database. Resolve the conflict by using a value ...

Lync Server 2010

A User ID attribute value is already being used by another valid user in the database. Resolve the conflict by using a value that isn't already taken, or deleting one of the users from AD.

The DN of the user whose User ID User Replicator tried to replicate is:
%1
This update came from domain:
%2
Cause: Typically caused by having multiple user or contact objects in AD with identical msRTCSIP-UserId attribute values.
Resolution:
Use a value that isn't already taken, or delete one of the offending users. You may use Dbanalyze to diagnose the problem.

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