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Exchange Team Blog
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How to work with Inactive Mailboxes

The_Exchange_Team's avatar
The_Exchange_Team
Icon for Microsoft rankMicrosoft
Jan 29, 2019
It usually starts with the following question: Is there a way to release the license of an Exchange Online user that left the company, but at the same time, keep the mailbox content? To get this done...
Updated Jul 01, 2019
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Tips 'n Tricks
Deleted's avatar
Deleted
Jan 29, 2019
The UI (PowerShell) states that it may take an hour to kick-in, so we've always measured this time window before removing an account (such as moving to the cloud immediately before off-boarding). Can we ignore that 60 minute warning/SLA and rely only on LitigationHoldEnabled?

Also, yes, as Coert K said, Microsoft has recommended we use retention policies in the security and compliance center instead, so please discuss the recommended best practices with these policies as well.

Deleted's avatar
Deleted
Jan 29, 2019
Policies are Best Practice but a pain to manage with automation. There is still a requirement to split bunches of 10K users (was 5K before) across policies. I use a modulus on the Guid's HashCode to provide as much as randomness and balance as possible.

Indeed, LegalHold is far easier to manage however it's the old-school way to do it (and the question is why is the Exchange Team recommending a legacy pathinstead of the a modern path :))

  • Deleted's avatar
    Deleted
    Jan 29, 2019
    Even if you wouldn't have a message like that (wait for 60 minutes), you have to understand that Exchange Online is a huge environment, in which replication of settings may not be done instantly. Because of this, even if you are not informed that you have to wait, as a best practice my advice will be to wait.

    Related to the question about which Hold option should be recommended (legacy from Exchange Online, or new ones from Security & Compliance), indeed, Microsoft recommends the new ones. Even so, it is up to you (until the time you'll be forced to use just the new ones) which one is most suitable for you, when speaking about moving a mailbox into the Inactive state.