Abstract: From time to time it happen that a Exchange mailbox / database got corrupt. This might happen due to a crash or a software bug. Since Exchange 2010 you can use the power shell to start a repair command.
The usage is quite easy and can be found here. So if you wish to run a fix against a whole DB including all kind of checks you can run New-MailboxRepairRequest as seen below:
New-MailboxRepairRequest -Database "enclavemaildb01" -CorruptionType ProvisionedFolder, SearchFolder, AggregateCounts, Folderview
You can monitor the progress in the eventlog on your mailbox server via the IDs 10044,1004,510046,10047,10048,10049,10050,10051,10059,10062 as written here.