To copy all Outlook emails to an external hard drive, export your mailbox to an Outlook Data File (.pst) and then transfer that file to the drive. This creates a portable, complete backup of your emails, contacts, calendar, tasks, and notes that you can store safely offline.
Before you start: download all your Outlook emails
Outlook defaults to downloading only the past year of email, so your backup might be incomplete unless you change this setting. If you also need to save messages from a different provider, you can download email from Yahoo to consolidate your archives. To ensure your exported .pst file contains your entire mailbox, open Outlook, go to Account Settings, then Account Name and Sync Settings, and move the slider to "All." This forces Outlook to download every email from the server before you export.
How to copy Outlook emails to an external hard drive using classic Outlook
- Open classic Outlook for Windows.
- Click "File" > "Open & Export" > "Import/Export."
- In the Import and Export Wizard, select "Export to a file" and click "Next."
- Choose "Outlook Data File (.pst)" as the file type and click "Next."
- Select the email account or folder you want to export. Ensure "Include subfolders" is checked to capture all contents like Inbox, Calendar, Contacts, and Tasks.
- Click "Browse" to choose your external hard drive as the destination. Enter a file name and click "OK."
- You may be prompted to set an optional password for the .pst file. Click "Finish" to begin the export.
How to copy Outlook emails to an external hard drive using new Outlook
- Open the new Outlook for Windows.
- Go to "Settings" > "Files" > "Export" > "Get started."
- Follow the wizard to select the mailbox or specific folders you want to back up.
- Choose your external hard drive as the save location and complete the export.
Note: In the new Outlook, calendar and contacts items saved in the exported .pst file are currently read-only. For full editability, use classic Outlook for those items.
Safely copy the PST file to your external hard drive
Exporting directly to an external drive can cause file corruption if the connection is interrupted. Instead, first export the .pst file to a local folder on your computer (such as your Documents folder). This two-step process ensures a stable transfer. Avoid saving or exporting your .pst file directly to a OneDrive location, as OneDrive will block automatic syncing for Outlook .pst files.
Important: PST file size limits and password options
PST files created by Microsoft Outlook 2013 or 2016 have a maximum size limit of 50 GB, while older versions might be limited to 20 GB. Exceeding these limits can lead to export failures or file corruption. During the export process, you have the option to set a password for the .pst file, which adds a layer of protection to your backup.
How to verify your Outlook email backup
- Open Outlook on your computer.
- Go to "File" > "Open & Export" > "Open Outlook Data File."
- Navigate to the .pst file on your external hard drive and open it.
- Check that all your emails, contacts, calendar items, tasks, and notes appear and are accessible. If everything looks intact, your backup is successful.
A note for Mac users
The direct .pst export method described here is for Windows only. For Outlook for Mac, use Time Machine to back up your entire system, including Outlook data, to an external drive. This ensures all your emails, calendar, and contacts are preserved as part of a complete system backup.
