1. Open the Microsoft 365 Compliance Center


Open https://compliance.microsoft.com/

  1. Create a new Content Search


– Select Content Search in the menu under Solutions
– Click + New Search

New Content Search

  1. Enter a name and description


Give your content search a recognizable name and description and click Next. This helps you later with identifying the correct content search.

Export Mailbox Office 365

  1. Select Exchange Mailboxes


To export a mailbox, turn Exchange Mailboxes on and click on Choose users, groups, or Teams

Export mailbox office 365 to pst

  1. Select the mailbox to Export


The next step is to select the mailbox that we want to export. Select or search for the correct user and click on Done

And click on Next to continue to the Conditions.

Select user in Content Search

  1. Leave Conditions empty


We want to export the complete mailbox, so we can leave the conditions empty.
Just click Next

Content Search Conditions

  1. Complete the Content Search


Review your Content Search and click Submit to start it.
Click Done to close the New Search screen

Review content search for export

  1. Wait for the search to complete


Depending on the mailbox size it can take a couple of minutes to complete the content search. Wait for the status to change to Completed in the Content Search scene. (Click Refresh occasionally to update the status)

content search completed

  1. Export the Office 365 Mailbox to PST


1. Click on the Content Search that we have just created
2. Select Actions
3. Choose Export results

Export results to pst

  1. Export Options

We can now select what and how we want to export our mailbox.
– Output Options: All items, including ones that have unrecognized format…
– Export Exchange Content as One PST file for each Mailbox.

Click Export to start the export

Export Microsoft 365 mailbox to pst

  1. Download the Office 365 export mailbox PST file


Again, it can take a couple of minutes for the download file to get ready.

– Open the Export tab in the content search screen
– Select the Export job to view the status

It can take a couple of minutes depending on the mailbox size. You can click on refresh to update the status, and wait for it to be completed.

Export job completed

  1. Download eDiscovery Export Tool


To download the PST files we will need to use the eDiscovery Export Tool.
As mentioned earlier in the blue note, you will need to use Edge for this step or use a ClickOnce browser extension in Chrome or Firefox.

Click Download Results to download the tool

Download PST from Office 365

  1. Approve the download


A new tab will open that will download the eDiscovery Tool. Click Open in the security warning

Open eDiscovery Tool

  1. Copy the Export Key


Before you can start the download, you will need to copy the export key from the Compliance Center.

export key

  1. Download the PST File


The last step is to start the download in the eDiscovery Export Tool.

1. Paste the key that we copied
2. Enter a location for the PST file
3. Expand Advanced Options and give the PST file a meaningful name

And click on Start

Start Download of PST file

  1. Wait for the download to finish

Depending on the size of the mailbox, the download can take some time. Wait for it to
finish and open the PST file in the location that you specified.

Download progress o365 pst file

You can also use these steps to download multiple mailboxes at once. Just select multiple users or mailboxes at step 5 and makes sure that you select one pst file for each mailbox in step 10.