When importing from PST files exported from an IMAP Server, the messages might not be showing when viewing them in Outlook although they are there. The messages are visible in OWA (Outlook Web Access) and you cannot move emails into the folders when this is done from OWA.

This is because when you import the PST, the messages are imported with the IMAP message format and need to be changed to IPF.NOTE format.

Download the ExFolders from the Microsoft website or from the tools page here.
Extract Exfolders.exe into C:\Program Files\Microsoft\Exchange Server\V14\Bin
Run the Registry file and import it

Make sure you have ‘Manage As’ permissions on the mailboxes you need with the logged in user.

Open ExFolders from the bin folder

Goto Tools and Options
Enable Logging to File

Goto File and select Connect with
Type: Mailboxes
Connect by: Database
Select the GC server
Select the Mailbox Database
You should see all the mailboxes listed

Goto Tools and open Custom Bulk Operation
Select Mailboxes as your Base Folder
Enter (&(0x3613001E=IPF.Imap)) in the Overall Filter
Click on the Add button and select Other Folder Properties and click OK
Select Action as Modify
Select PR_CONTAINER_CLASS : 0x3613001E as Property
Enter IPF.Note as Value
Click OK and OK

This should process the folders and emails. From here Exfolders will walk through the mailbox container(s) and change each instance of the PR_CONTAINER_CLASS from IPF.Imap to IPF.note