The Microsoft Exchange Unified Messaging service on the Mailbox server couldn't find the prompts for the "%1" language pack. ...

The Microsoft Exchange Unified Messaging service on the Mailbox server couldn't find the prompts for the "%1" language pack. This language won't be available on this server until the problem is resolved. If the language pack has just been uninstalled, this problem may be caused by delays in directory replication and should correct itself. Otherwise, there may be a problem with the installation of the language pack and you should attempt to remove, and then reinstall it. Additional information: "%2"