Very slow work of a mailbox in Exchange 2010

      Faced with an unexpected problem: a single mailbox in the vault is very slow and the Outlook and OWA. After a long diagnostic wake up the user creates a tasks for subordinates from Outlook. The solution was to reset the incorrect synchronize tasks. This can be done manually:
1. Click on the task with an exclamation point in a condition
2. Selected from single copies of tasks
3. click "save this copy"

or by running the Outlook with a parameter /resettodobar