In order to export mails from Exchange 2003 (should not exceed 2 GB) you will have to copy Administrator user into another user “admin” and give that user the rights to access all other mailboxes.
You will have to navigate to the Mailbox store
Right click the mailbox store and click on Properties
Go to Security tab and add the new user (Admin) and give it full control as below
Apply, then sign out of the windows session to the Exchange machine and use the newly added domain admin to login and then open the Exmerge application
Select the second step (Extract or Import)
Select the Exchange name and the DC (They should be set automatically)
Select the users that you want to be exported (shouldn’t exceed 2 GB).
Select the local language
Select the destination folder (In my case I mapped a network drive)
Save settings for later use if you want or just click Next.
Once done, the mailbox will be exported.
Importing into Exchange 2013
In exchange 2013 Open the EMS as administrator
Before you start, you should move all the PST files into a shared folder in the network and add the “Exchange Trusted Subsystem” user to its permission.
The same user should be added to the security tab
Providing import and export permission on Exchange 2013
In order to import the PST files to Exchange 2013 users you will have first to assign the Exchange Admin account the capability of importing these PST files then sign out from the EAC portal and back in
To do so you will have to go to EAC then go to Permissions and double click on the Recipient Management
Click Add and select the Mailbox Import Export and click Add then OK
I will add members to this role group
After signing in back to the EAC with the administrator I got the Import PST options.
For Management shell usage
Importing PST using EAC and following up with EMS
Importing Single folder from source PST file into a target folder in email
Importing the folder Sent Items from the file basakc_backup.pst into target folder Sent Items in Mhamada user.
The parameter -TargetRootFolder will create a folder inside the existing Sent Items folder
Importing large items into mailbox in Exchange