Cause of error
During a PST migration, the 10GB default size for a PST file has been exceeded. This limit is set because of the resource load on the server during PST migrations.
On the Advanced Options page, in the Support Options dialog box, enter:
Important: This advanced option should be used with the understanding that the User's migration may not operate properly, and should be a last resort because of the effect this can have on server resources.
The property value <GB size> is the new maximum PST gigabyte size for the migration. This number should match the PST file size.
If it is necessary to control size, PST files can be recreated using a subset of folders from Outlook, as well as using available online tools.