Optional. Controls the placement of migrated folders in the target mailbox. When set to true, migrating more than one PST file for the same user causes Policy Manager to merge the identically-named folders.
When set to false, Policy Manager appends a number to the folder names, if necessary, and thereby keeps the folders separate. For example, if two folders at the same level are called "MyFolder", Policy Manager creates "MyFolder" and "MyFolder 1".
If MergePSTFolders is set to false and you migrate three PST files that have the display name "Personal Folders", and all contain top-level folders "Inbox" and "Sent Items", then you get a structure like the following:
PST Migration (specified by MailboxFolder) Personal Folders Inbox Sent Items Personal Folders 1 Inbox Sent Items Personal Folders 2 Inbox Sent Items