Migrating an exchange 2003 user mailbox to another user without using exmerge.

Have a user mailbox that is extremely large and the user is an executive Manager that doesn't want to archive mail.  As an interim solution until we migrate to Exchange 2010, I'd like to create a new 'account' and migrate all of the mail from the 'primary' account mailbox to the 'secondary' mailbox.  The intent being that the user will connect to both 'mailboxes' in Outlook.  This will allow faster processing on the 'primary' mailbox and still allow the user to connect to all old mail, etc.  I tried deleting the mailboxes and then 'reconnecting' them to each other's 'account' in the hopes of doing it quickly without using exmerge. Because I think exmerge is going to take about a day and a half and the user doesn't want to be without mail for that long, etc.

Wondering if anyone has tried anything similar or has an idea about another way of accomplishing this.

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Large mailbox move:
a) You can exmerge by date range (6 months) and then import it into the other 2003 mailbox.
b) You can schedule this after hours so that the executive is not affected.

I'd rather exmerge and import it in Ex 2010 over the weekend.
Keep everything since 1/1/2011 and then exmerge the rest out as .PST and import it in Exchange 2010 on a temp-mailbox.
Then move-mailbox move for rest of the emails for 2011

my $.02

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Yes, you can do the delete and reconnect.
As sunnyc7 says, the user can still use their mailbox while the content is emerging in...
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techeezAuthor Commented:
Ok, Looks like the best way will be to use exmerge then :)

techeezAuthor Commented:
I was hoping to find a solution that didn't use exmerge. But the solution provided will work.
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