Using mailbox retention (in-place hold)

Another method for preserving emails that scales more effectively than the shared mailbox hack is to use a retention policy (sometimes called litigation hold). Enabling mailbox retention prevents the mail from being deleted even if the mailbox itself is no longer available.

It is important to keep in mind that to use mailbox retention as a strategy, the administrator must have at least an E3 license, though our tests have shown that it can be enabled for users who have lower end accounts such as Business Premium. (You must also be in the legal hold, or more typically a discovery management, administrative role.) Thus, if you're connecting through a Microsoft partner account supporting the end customer, you cannot use your delegated access permissions to perform these activities. This may lead to additional costs for the end customer to create administer accounts for you to use.

To enable in-place hold on a mailbox, connect to the Exchange Online remote session in PowerShell, as we described in Chapter 2, Using PowerShell to Connect to Office 365 Services. Once you're connected, use commands like these to set the hold:

Get-Mailbox -Identity user@myemaildomain.com | Set-Mailbox -LitigationHoldEnabled $true

If PowerShell isn't your thing, fortunately you can also enable in-place hold from the Exchange admin center. Browse the user's mailbox under recipients, click to highlight it, and look for the hold option along the right-hand menu, as shown:

Hold status

You may notice that there's no link shown to let us change this setting. Don't worry, you can edit the mailbox and find the option under the mailbox features section. Scroll down until you're just above Mail Flow and you should see the link to enable in-place hold there. Note it may be called the Litigation hold Dashboard:

Enable hold in Exchange admin center

Does that seem a bit cumbersome to you? We agree. Recently, Microsoft also made this option available directly under user management in the Office 365 admin portal. Select a user, and you'll find it under Mail Settings, like so:

Enable hold in admin portal users

Learn more about in-place/litigation hold at:
In-Place Hold - https://technet.microsoft.com/en-us/library/ff637980(v=exchg.160).aspx.