WARNING: [301-21-71-80020009] Unable to migrate contents of folder '3D91FA77. DCCCD.DSC1.100.1676D73.1.148C5.1'
Message filtered (Large Mail) UNKNOWN : Unsupported message type. Filtering message 'Unread Mail' in folder 'UNKNOWN'
The folder name may not be in a format that can be read properly by the Groupwise client during the migration. Note that the folder name above is displayed as '3D91FA77. DCCCD.DSC1.100.1676D73.1.148C5.1' and may not actually be a folder containing data.
Most times, this warning can be safely ignored as it is referring to a folder which is improperly formatted or corrupt.
Open the source mailbox in the Groupwise Client and try to locate the offending folder to see if it contains data which is required for the migration or if it is simply not something which should be migrated. The folder name may need to be changed in order to allow it to be migrated.