The Export Results dialog is displayed after an export has been completed using the Export dialog and the Show results when export completes option was checked:
The dialog displays a list of all of the mailboxes or Public Folders that were included in the export, and the status for each object. If an object fails to be exported, the relevant node can be expanded to obtain further details. Any of the nodes under the Errors node can be double-clicked to view the details of the error(s) that occurred. The results can also be saved to a log file by clicking the Save... button. Selecting the Only save details of the errors that occurred option will cause only mailbox or Public Folders that failed to be exported to be included in the log file.