Understanding Outlook Backup and Restore
Before jumping to restoring Outlook, it’s helpful to know how Outlook stores your data:
- PST file (Personal Storage Table): Used in POP and manual exports. It contains all your Outlook data, emails, attachments, contacts, calendar, etc.
- OST file (Offline Storage Table): Created when using Exchange, IMAP, or Microsoft 365 accounts. It mirrors the mailbox data stored on the mail server.
- AutoArchive files: AutoArchives that you have created in Outlook to store old emails in a separate PST file.
When you need to back up Outlook data, knowing the data file type will help you with Outlook restoration.
Methods of Restoring Outlook Backup (Microsoft 365, 2021, 2019, etc.)
Pro Tip:
If you only want certain folders (like Inbox or Contacts), you can selectively import them instead of the whole backup.
Method 1: Restore an Outlook Backup (PST File)
If you’ve previously exported your Outlook data into a .pst file, follow these steps to restore using the Import/Export wizard:
Where are Outlook backups saved?
PST file:
OS and Outlook versions: Windows 10/11 (Outlook 2016–2021, Microsoft 365)
Location: C:\Users\\Documents\Outlook Files.
OST file:
OS and Outlook versions: Windows 10/11 (Outlook 2016–2021, Microsoft 365)
Location: C:\Users\\AppData\Local\Microsoft\Outlook.
- Open Outlook.
- Go to File > Open & Export > Import/Export.
- Choose Import from another program or file, then click Next.
- Select Outlook Data File (.pst) and click Next.
- Browse to your backup .pst file and choose Replace duplicates with items imported (recommended).
- Choose the folder where you want to restore the data, if you need it to be in the current mailbox, select the top-level email address in the list. Or import it into a new one and click Next
Method 2: Restore Outlook Data from OST (Offline Folder File)
If you’ve backed up an OST file or recovered one from an old system, you can’t directly open it like a PST. OST files are tied to the Outlook profile that created them.
However, you can restore data in two ways:
Option A: Reconnect to the Mail Server
If your old OST is linked to the same Exchange or IMAP account:
- Re-add your email account in Outlook.
- Let Outlook sync automatically. It will recreate the OST file and re-download your mailbox.
Option B: Convert OST to PST
If the old profile is unavailable or has any orphaned OST files, convert the OST file into PST format using a reliable tool such as Remo OST to PST Converter.
As Microsoft does not provide a built-in converter, manual conversion is impossible unless the mailbox is accessible. You will need an effective, trustworthy tool for importing OST file data into Outlook.
Looking to convert OST to PST?
Remo OST to PST Converter safely converts corrupt, damaged, orphaned, or inaccessible OST to PST.
Step 1: Download and install the Remo Convert OST to PST tool on your computer.
Step 2: Launch the software, choose your IMAP account, select Open OST File (If you want to manually locate the OST file) or Find OST File (If you want the software to automatically locate the OST file), and click Next.
Step 3: Choose the Browse button to choose a location converted PST file and click Convert.
Step 4: Now, the Remo OST to PST converter tool starts converting the OST file to a PST file.
After converting the OST into PST, the software will display a message saying the OST file conversion has completed.
Once completed, you can choose to back up the PST file or import the PST file into Outlook
Method 3: For Outlook for Mac
Outlook for Mac stores data in an OLM file instead of PST. Here’s how to restore your Outlook backup on Mac:
- Open Outlook for Mac.
- Go to File > Import.
- Choose the Outlook for Mac archive file (.olm) and click Continue.
- Select the OLM file you backed up and click Import.
- Once done, the imported folders will appear in the On My Computer section.
Method 4: Restore Using Outlook AutoArchive
If you’ve lost old emails but had AutoArchive enabled, Outlook may have already created a backup file for you.
To restore it:
- In Outlook, go to File > Open & Export > Open Outlook Data File.
- Browse to the archived PST file, usually found in C:\Users\<username>\Documents\Outlook Files\archive.pst
- Select it and click OK.
- The archive folder will appear in your Outlook sidebar. You can drag or copy emails back to your main mailbox.
Restore Outlook to Default Settings (Optional)
If you’re troubleshooting or want to start clean before restoring, you can reset Outlook to its default state.
This approach ensures no old settings or corrupted profiles interfere with your restoration.
- Close Outlook.
- Open Control Panel > Mail > Show Profiles.
- Click Add to create a new profile, or Remove the old one.
- Launch Outlook and set up your email again.
- Then, use the Import and Export Wizard to import your backup file.
Frequently Asked Questions
1: How to back up Outlook 365 emails from the browser?
Outlook Web doesn’t offer a direct export option. For backing up Outlook 365 emails, open Outlook on Windows/Mac, add your Office 365 account, and export to a PST file. Alternatively, drag emails to a local folder or use a third-party backup tool.
2: How to restore an Outlook backup on Mac?
Outlook for Mac can only import PST files, not OST. Go to File > Import > Outlook for Windows archive (.pst) and select your backup. Outlook will restore your emails, contacts, and calendar into a new folder group.
3: How do you restore a BAK file?
A BAK file is just a backup copy, so you restore it by renaming it to the original file extension (for example, .pst) and replacing the existing file. If it’s an Outlook .bak from a PST repair, rename it to .pst and then import it into Outlook.
Bonus: How about an Automatic Outlook Backup and Restore option? (For Windows)
Remo Outlook Backup and Migrate
Instead of dealing with the hurdles and drawbacks of exporting PST or OST files and importing them manually, use Remo Outlook Backup and Migrate to easily back up and restore your entire Outlook data (including all settings, rules, and customizations).
It supports backing up Outlook data to an external hard drive, SSD, NAS, or Remo Backup Cloud Storage (25 GB).
You can choose to save specific Outlook files and folders as a backup or restore/migrate them to another computer whenever needed.
About the Author: Tony Landry
Tony Landry is a Web Content Editor at Remo Software. He loves to write, edit, and manage content for users trying to troubleshoot and fix problems on Windows, Outlook, storage drives, and Cloud storage networks. With an aptitude that transcends writing, Tony is recognized as a Microsoft Outlook, Word, and PowerPoint expert. His comprehensive solutions…
