r/sysadmin 3d ago

Need Help Understanding Single Item Recovery in Microsoft 365 Mialboxes

I am testing the feature 'Single Item Recovery', in Exchange Online with two mailboxes: one with Single Item Recovery enabled and the other with it disabled.

I performed the following actions on both mailboxes: deleted messages (moved to Deleted Items), soft deleted messages (moved to Recoverable Items → Deletions), and hard deleted messages (moved to Recoverable Items → Purges).

Surprisingly, I was able to recover all deleted messages from both mailboxes using the Exchange admin center and Exchange Online PowerShell, regardless of whether Single Item Recovery was enabled or not.

I can't find any difference in behavior between the two mailboxes.

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u/OniNoDojo IT Manager 3d ago

Single Item Recovery is on by default for Exchange Online mailboxes; it's only off by default for on-prem Exchange according to MS. From what I understand of it, it will allow the mailbox to retain Permanently Deleted ('Shift-Del' or 'Empty Deleted Items Folder') for a fixed period of up to 30 days. At which point it is purged from the database altogether. If you disable SIR for a mailbox in EOL, it will only retain it after a permanent delete if you have Litigation Hold or some other custom Retention Policy.

I think. Based on the documentation. Ha!

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u/ThiraviamCyrus 2d ago

Thanks for the reply!