In our hybrid environment, we manage all user mailboxes through Microsoft 365. When an employee departs, we need to keep their mailbox data for about ten years but prefer to remove their Microsoft 365 license after 30 days. I've heard that converting the mailbox to a shared one is one solution, but I'm unsure of what happens to the mailbox and its archive after the license is revoked. Specifically, if the mailbox is under 50 GB, will the shared mailbox remain but the archive be deleted?
There are suggestions to place the mailbox on litigation hold before removing the license, but I'm uncertain about its long-term status once the user account stops syncing to Entra ID. Will the mailbox become invisible? Some believe I should also remove all email addresses so it stops receiving mail, which would be a plus.
Our current process is very manual and includes running eDiscovery searches and exporting mailbox contents, which is time-consuming. We want an automated solution that allows us to retain mailbox data, stop new emails after 30 days, and streamline the whole workflow using PowerShell. What's the best approach for this?
5 Answers
Backing up the mailbox is crucial. There are many backup solutions for Microsoft 365 that can keep your data safe for those ten years. Relying solely on retention policies isn’t enough; you need a real backup strategy.
Using a solid mail archiving solution is key here. I would recommend steer clear of PST files for long-term storage since they come with management headaches. If you’re in a hybrid setup, just convert to a shared mailbox, hide it from the Global Address List, and implement restrictions to stop new mail from arriving. After that, removing the license should be straightforward, but remember to backup any OneDrive data too!
If you’re on Microsoft 365 E3, consider utilizing the retention model instead of going for shared mailboxes. It might save you a lot of hassle in the long run. Check these resources for more info: [Inactive Mailboxes](https://learn.microsoft.com/microsoft-365/compliance/inactive-mailboxes) and [Retention Policies](https://learn.microsoft.com/microsoft-365/compliance/retention-policies-exchange).
Converting the user to a shared mailbox and then removing the license can simplify things. Don't forget to hide it from the address list so it doesn't show up accidentally. You might want to script this for efficiency!
Be careful when moving a user to a directory that doesn’t sync—it could result in the complete deletion of their mailbox. Retention policies in Microsoft 365 could help ensure that data is maintained, but you’ll need to use Purview for any recovery if that happens.
Exactly! The issue isn't just retention; it's about having an actual backup plan. The built-in tools aren't adequate for long-term storage. A proper 3-2-1 backup approach is essential.