hello,
You can do that via VBA. I find a article online which may be just what you want. Below is the codes:
Sub ExpandAllMailFolders()
Dim objCurrentFolder As Outlook.Folder
Dim objPSTFolders As Outlook.Folders
Dim objFolder As Outlook.Folder
Set objCurrentFolder = Application.ActiveExplorer.CurrentFolder
'Specify a specific pst file
'Change "PSTName" to the name of your own Outlook PST file
Set objPSTFolders = Application.Session.Folders("PSTName").Folders
For Each objFolder In objPSTFolders
Call ProcessFolder(objFolder)
Next
DoEve
