Export-MMExPublicFolderMapping has an optional
-TargetMailboxSize parameter
-TargetMailboxSize
Specifies maximum size allowed for target public folder mailbox.
Required? false
Position? 3
Default value 15GB
Accept pipeline input? false
Accept wildcard characters? false
So the 15 Gb is just the default value, but if you need to work with larger folders, you can add the corresponding value in the command line.
