How to Backup Office 365 Email: Step-by-Step Guide

Updated 15 November 2026 · Standard formula, shown below

This guide explains how to create a reliable backup of your Office 365 (Microsoft 365) email, whether you want to archive old messages, protect against accidental deletion, or prepare for leaving the service. You’ll learn several methods—from built-in export tools to third-party software—and get clear steps for each. No special skills are required beyond basic familiarity with Outlook and file management.

What You’ll Need

An Office 365 or Microsoft 365 account with email access (admin rights are not required for personal mailboxes).
Outlook desktop client installed (for the export method). If you don’t have it, you can use the Outlook web app and download a single folder as a .pst file, though it’s limited to one folder at a time.
Sufficient free disk space on your computer or an external drive—email backups can be large (several GB).
Optional: A third-party backup tool if you want automated, cloud-based backups (see tips).

Step-by-Step

Method 1: Export to PST using Outlook Desktop (Recommended for full mailbox)

Open Outlook desktop app and sign in to your Office 365 account.
Click File in the top-left corner.
Click Open & Export and then choose Import/Export.
In the wizard, select Export to a file and click Next.
Choose Outlook Data File (.pst) and click Next.
Select the folder you want to back up (e.g., your entire mailbox by selecting the top-level folder, or just Inbox, Sent Items, etc.). Check the box Include subfolders if you want everything.
Click Next, then choose a location to save the .pst file (e.g., an external drive). You can also set a password (optional—if you forget it, the backup is unusable).
Click Finish. Outlook will start exporting. The time depends on mailbox size.
When done, you’ll have a .pst file that you can store safely. To restore later, use the same Import/Export wizard and choose Import from another program or file.

Method 2: Export a Single Folder from Outlook on the Web (Quick, no desktop app)

Go to outlook.office.com and sign in.
Right-click on the folder you want to back up (e.g., Inbox) and select Download folder (or Export folder in some versions).
Your browser will download a .pst file containing that folder and its subfolders.
Repeat for each folder you need. This method does not export the entire mailbox in one go.

Method 3: Use a Third-Party Backup Tool (Automated and cloud-based)

Choose a reputable backup service (e.g., Veeam, CodeTwo, or AvePoint—research current options).
Sign up for an account and install the software or connect it to your Office 365 tenant (you may need admin permissions for full mailbox backup).
Follow the tool’s setup wizard to select the mailboxes you want to back up.
Schedule backups to run daily or weekly, and choose a storage destination (cloud storage or local).
Monitor the first backup to ensure it completes successfully.

Common Mistakes

Forgetting to include subfolders when exporting—you’ll miss important emails.
Setting a password on the .pst and then forgetting it—there’s no recovery.
Saving the backup only on the same computer that could crash or be stolen.
Assuming that Office 365 automatically keeps backups forever—Microsoft retains deleted items for a limited time (typically 30 days, or up to 93 days with litigation hold), but it’s not a personal backup.
Not testing the backup after creation—always open the .pst to verify it works.

Tips

Store your .pst file on an external drive or cloud storage (like OneDrive or Google Drive) for redundancy.
If your mailbox is huge, export in chunks (e.g., by year) to avoid timeouts.
For ongoing backups, consider a third-party tool that automates the process—manual exports are easy to forget.
If you’re an admin, use Microsoft’s built-in eDiscovery or Compliance Center to export mailboxes for legal/archival purposes.
Keep a record of the backup date and what it contains—label files clearly.

Troubleshooting

Export fails with an error: Close Outlook and restart it. If that doesn’t help, try exporting a smaller folder first to isolate the issue. Make sure you have enough disk space.
Outlook says “The operation failed” when importing: The .pst file might be corrupted. Try a different location, or use the Inbox Repair Tool (scanpst.exe) that comes with Outlook.
Web export doesn’t show the option: Your organization may have disabled this feature. Contact your IT admin or use the desktop app.
Backup is very slow: Close other programs and let it run overnight. For large mailboxes, consider a third-party tool that handles large data more efficiently.
Can’t find the downloaded .pst file: Check your browser’s default Downloads folder, and be aware that some browsers may block the download—allow it if prompted.

Frequently Asked Questions

Can I back up Office 365 email without Outlook?

Yes, you can use the Outlook web app to download individual folders as .pst files, but it’s less convenient for the entire mailbox. Third-party tools also work without Outlook.

How long does Microsoft keep deleted emails?

By default, deleted items are kept for 30 days. If you’re an admin, you can extend this to up to 93 days using retention policies, but it’s not a substitute for a personal backup.

Is it legal to back up my own email?

Yes, as long as you have the right to access the mailbox. For business mailboxes, check your organization’s policy and any applicable data protection regulations.

What’s the difference between a .pst and a .ost file?

A .pst is a personal folder file used for archiving and backup. An .ost is an offline cache file that Outlook uses to work offline—it’s not meant for backup and can get corrupted.

Can I restore a backup to a different Office 365 account?

Yes, you can import a .pst file into another Outlook profile, but the emails will appear as if they were sent from that account. For a seamless migration, consider using a migration tool.

Do I need admin rights to back up my own mailbox?

No, for your own mailbox you only need access to Outlook. Admin rights are required only for backing up other users’ mailboxes or using certain eDiscovery features.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.