Microsoft 365 Export Mailbox to PST

Feb - 07 2023 | By

If you want to export the contents of a user in Microsoft 365 to a Outlook PST file follow these steps.  These all should be done using Microsoft Edge.  Microsoft Edge is the only one that seems to work with the export download.

Check that your username at Microsoft 365 can Export – Need to be a Global Administrator

Sign in at https://purview.microsoft.com choose Settings, Roles and Scopes, Role Groups, choose eDiscovery Manager, choose Edit, click Choose Users select your account, choose Select, choose Next, Next, and Save.

Export Steps

Now that the username has the ability to export content we can go through the steps.

Sign in at https://purview.microsoft.com

  • Choose Solutions – eDiscovery
  • Create a Case and in creating the Case it will prompt for a name.
  • Create a Search and in creating the Search it will prompt for a name for your Search.
  • Choose Add sources – select All Sources in the tenant, People only, Mailboxes only.  In the box below search type in the users email address or name. Check off their name and click Save and Close.
  • In the Query list select the user then click Export
  • Provide a name for the Export, choose Indexed items that match your search query.
  • No need to do anything with OneDrive and SharePoint items.
  • Under Messages and related items from mailboxes and Exchange online choose Export items with items report.  Choose Create .PSTs for messages where possible, Max PST package size set to 10GB.  There should be no need to change the check boxes for Organize data from different locations into separate folders or PSTs, Include folder and path of the source, Condense paths to fit within 259 character limit, Give each item a friendly name.  Click Export to begin the PST creation.
  • After your Export is started on the left it will list the user you are exporting under Data sources.  At the top you can click Process manger button to view the progress on your Export, when you click on the export you get all details about your export – how much time has elapsed and a rough estimate of time needed to complete, it will also show you how many items have been exported.
  • When Export is complete in Process manger button select your export it will list the export file(s) and provide you with the ability to download the PST and Reports.

Old methods…

Check that your username at Microsoft 365 can Export

  • Sign in at https://compliance.microsoft.com – New now https://purview.microsoft.com
  • Click Permissions from the menu on the left – New now choose Settings
  • Choose Microsoft Purview Solutions, Roles – New now choose Roles and Scopes, Role groups
  • Choose eDiscovery Manager
  • From Assigned roles, make sure Export is listed and that your username is listed here if not click Edit and add Export and choose your username to eDiscovery Administrator, then click Save.

Export Steps

Now that the username has the ability to export content we can go through the steps.

  1. Make sure your signed in at https://compliance.microsoft.com – New now https://purview.microsoft.com
  2. Choose Content search on the left menu – New now eDiscovery
  3. Choose New search from the menu at the top, under the Search tab – New now Classic eDiscovery,  Content Search, choose New search from the menu at the top.
  4. Provide a Name and description for the search – like Export Mailbox John Doe, click Next.
  5. In the Locations page turn on Status column for Exchange mailboxes, then click Choose users, groups or teams, type in the email address of the user you want to Export to a PST file, check their name click Done.  Then click Next.
  6. In the Define your search conditions, just click Next.
  7. On Review your search and create it, click Submit.
  8. On the Content Search page wait for it to show Completed, you can click the Refresh button at the top to update the status.
  9. When complete, click your Export at the bottom left under Actions menu choose Export results.
  10. On Export results, choose All items, including ones that have unrecognized format, are encrypted, or weren’t index for other reasons and choose One PST file for each mailbox. Then click Export.
  11. Go to the Export tab and watch the progress of your Export, you can click Refresh at the top to update the status.
  12. When completed click the Export for the Mailbox copy the Export key that is required to download your PST file.
  13. After copying the Export key click Download results at the top of the Window.
  14. It will ask you about opening a file, Microsoft.Office.Client.Discovery.UnifiedExportTool.application, choose Open
    Agree to allow the application to Run.
  15. It will ask for the Export key in the first box, paste the Export Key you just copied, click Browse to choose where to save the files, and from Advanced options I recommend choosing a name for the file otherwise it just names it export.pst.
  16. Wait for the download to finish and wait for the Close dialog then you will find a folder in the location you choose to save your export with all the information from the export.

Microsoft 365 Export PST File Size Limit

Microsoft has the default size of the exported PST files to 10GB, you can increase or decrease the file size.  Larger PST files are more likely to become corrupted.

You can create a registry import file with the following

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Client\eDiscovery\ExportTool]
"PstSizeLimitInBytes"="21474836480"

Double click the newly created Reg file you have just created and agree to import the Registry change.

Where the PstSizeLimitInBytes can be 4294967296 – 4GB or 8589934592 – 8GB or 10737418240 – 10GB or 2147436480 – 20GB or 32212254720 – 30GB.  The restart the eDiscovery download to export PST files in the new size.

After you are finished you should restore this PstSizeLimitInBytes back to the default setting you had.