The Microsoft Exchange Unified Messaging service on the Mailbox server detected corrupted user configuration data for user ...

The Microsoft Exchange Unified Messaging service on the Mailbox server detected corrupted user configuration data for user "%1". This data contains information such as whether the user has previously signed in to their mailbox or has turned on automatic replies because they're away. It also contains any personalized voice mail greetings the user has recorded. The Mailbox server will use default configuration data for the user.