To save emails to an external hard drive, you export them from your desktop email client directly to the drive, creating a portable backup that frees up space in your inbox. This process creates a secure offline copy you can access anytime, even without an internet connection.
Before you save emails to an external hard drive
Connect your external hard drive to your computer using a USB cable and wait for the operating system to recognize it. Before exporting, organize your emails into specific folders or categories within your email client, this makes selecting and exporting the right data faster and reduces the chance of missing important messages.
One critical warning: avoid saving PST files directly to a folder that syncs with OneDrive. OneDrive blocks automatic syncing for PST files, which can cause corruption or failed backups. Always choose a folder on the physical external drive that is not being synced to any cloud service.
How to export all Outlook emails to a .PST file
To copy all Outlook emails to an external hard drive as a single portable file, use the built-in export feature. This creates an Outlook Data File (.pst) that stores your emails, contacts, calendars, and tasks.
- In the classic Outlook desktop application, go to File > Open & Export > Import/Export.
- Select "Export to a file" and click Next.
- Choose "Outlook Data File (.pst)" and click Next.
- Select the mail folders you want to back up. Ensure "Include subfolders" is checked to capture all nested folders.
- Click Browse, navigate to your external hard drive, and choose a save location. Name the file clearly.
- Click Finish. Outlook will create the .PST file on your external drive.
After the export completes, you can verify the file appears on the drive. The .PST file can later be imported back into Outlook if you need to restore the data.
Alternative ways to save individual Outlook emails
If you only need a few specific messages instead of an entire mailbox, you have two simple options that do not require the full export process.
Drag and drop an email from Outlook directly into a folder on your external hard drive. This saves the email as a .msg file, which can be opened by double-clicking it in any Windows system with Outlook installed.
Alternatively, open the email, go to File > Save As, choose a format such as HTML or PDF, and browse to your external hard drive to save the file. This method preserves the email’s content and formatting in a widely readable format.
A note for 'New Outlook' for Windows users
The "New Outlook" for Windows app does not include the classic export-to-PST feature. To use the method above, you must have the classic Outlook desktop application installed on your computer. If you only have New Outlook, you may need to switch to the classic version or install it separately to create PST backups.
How to back up Thunderbird emails to an external hard drive
Thunderbird stores all your emails, settings, and account data in a single profile folder. Backing up this folder creates a complete, restorable copy of your entire Thunderbird setup.
- Close Thunderbird completely. Do not leave it running in the background.
- Open File Explorer and navigate to the default Thunderbird profile location:
C:\Users\<YourUsername>\AppData\Roaming\Thunderbird\Profiles\ - Inside this folder, you will see one or more folders with names like
xxxxxxxx.default. Copy the entire profile folder that contains your data. - Paste the copied folder into a directory on your external hard drive.
To restore, simply copy the backed-up profile folder back to the same location, replacing the existing folder, before reopening Thunderbird.
How to verify your email backup
After saving your emails, confirm the backup is complete and functional before relying on it.
- Navigate to the folder on your external hard drive where you saved the exported data.
- For Outlook backups, double-click the .PST file. Outlook will open it as a separate data file, allowing you to browse folders and open individual emails. Check that attachments open correctly.
- For Thunderbird backups, open the copied profile folder and verify it contains files like
Mail,ImapMail, andprefs.js. You can also restore it temporarily to a test Thunderbird installation to confirm all messages are accessible. - Open several emails from different folders to ensure content, dates, and attachments are intact.
