Error: Cannot synchronize messages in the folder '\System Cleanup\Sync Issues\Server Failures' (4315553)

Errors are seen in the Mail Source Agent log:

CFolder::Synchronize Error -2147221221 Unknown Error. - MAPI_E_CORRUPT_DATA (Microsoft Exchange Server Information Store) File: 'aeMAPIFolder.cpp' Line: '560' (Folder: 'Server Failures', SourceKey: 'E0529A8FFC2C9143A5F1BB9A89101D0600000CD9E23F')
3/22/2011 6:32:42 AM MailExport::SynchronizeContent Error 2032 Cannot synchronize messages in the folder '\System Cleanup\Sync Issues\Server Failures'. Messages type 32.

And an automatic switch operation fails with the error:

MailKernel::IsReadyToSwitch Informational 2092 Synchronization status: Critical error found.