I am moving our Exchange 2007 to MS365. I have about 8 (out of 300) mailboxes larger than the 100gb limit for E3. In addition the consultants doing the migration have indicated that their max is 92gb (because of overhead).
I can export the mailboxes via PowerShell export-mailbox and I see that it has a date range parameter that will let me export only older info.
BUT how do I trim the older item from the exchange server mailbox - is there and option in export-mailbox to remove items? I'm not seeing it.
Is there a better approach? A third party app?
Also, I need the items to disappear immediately - can setting the retention policy to 0 achieve that?
Aloha from Hawaii!!