Migrating all the email mailboxes will take time so removing unnecessary email is vital. Ask all the users to archive older emails and empty their deleted items folder to shorten the migration task. Each user will need to do this on his/her own, from Outlook, although you may have to assist in the process. While it is not vital to carry out this task, if they do not, then expect significantly longer email database checks and actual migration times later in the process.
The process for each user is very simple assuming they are using Outlook as their email program.
Empty the deleted items by clicking the Tools menu and selecting Empty "Deleted Items" Folder.
Archive emails to a PST file by selecting the File menu and clicking Archive.
Select Archive this folder and all subfolders and select the top item (normally, something like Mailbox—David Overton).
Set a date, such as 1st January 2008, that all items older than will be stored in the archive file.
Ensure...