The upside is that you get a clean mailbox immediately, which is what you want.

Create a new mailbox and switch it in to replace the old mailbox.

The downside is that the Managed Folder Assistant might not process the mailbox for another seven days (the workcycle used in Exchange Online), and you will have to wait for its completion to see the results of its work. The upside is that the Managed Folder Assistant does its processing in the background and can remove items permanently.

Apply an Exchange mailbox retention policy to the Inbox folder to remove all items after they are “x” days old (let’s say 7).

Ten searches are needed to remove our 100,000 items. The upside is that Search-Mailbox can remove the items permanently the downside is that Search-Mailbox only returns 10,000 items at a time, so it can only remove 10,000 items.

Use the Search-Mailbox cmdlet to remove items from the mailbox.

Here are three obvious actions that can be taken:

This is well under the Exchange Online folder limit of 1 million items, but it’s still a bunch of data to process. The other available options are administrative actions. Let’s assume that you want to cleanup a mailbox with an Inbox folder of 100,000 items.

The OWA options are user-driven and can be applied to any mailbox to which a user has access. It might be possible to do the job manually by selecting and removing the messages, or using OWA’s Cleanup mailbox option, but both options can take a long time to run and move items into the Deleted Items folder, where you might want to remove the items permanently.

It’s quite common to find that a clean-up is needed for shared mailboxes.

“ How can i delete a whole bunch of emails in a shared mailbox using the online mail browser? (instantly)“ See this post for more information.Īnother question, this time from the Facebook Office 365 group: Note: Search-Mailbox is due for deprecation on July 1, 2020.

Outlook 365 delete emails at exit