Removing an Outlook data file from your profile prevents it from loading during future sessions. If you’re wondering how to delete Outlook data file properly without losing important emails or breaking your Outlook setup, you’ve come to the right place. This guide walks you through every method, from simple profile removal to permanent file deletion, with clear steps for Outlook 2016, 2019, 2021, and Microsoft 365.
Understanding Outlook Data Files
Outlook uses two main types of data files: PST files for POP3 and IMAP accounts, and OST files for Exchange, Microsoft 365, and Outlook.com accounts. These files store your emails, contacts, calendar items, and other data locally on your computer. Knowing which type you have helps you choose the right deletion method.
PST files are standalone archives you can move or delete freely. OST files are synchronized copies of server data—deleting them doesn’t remove anything from the server, but it does remove your local cache. You might want to delete these files to free up disk space, fix corruption issues, or start fresh with a new profile.
Why You Might Need To Delete An Outlook Data File
- Your Outlook is running slowly or crashing frequently
- You’re getting error messages about data file size limits
- You want to remove an old email account from your profile
- You’re troubleshooting synchronization issues
- You need to free up hard drive space
- You’re preparing to migrate to a new computer
How To Delete Outlook Data File From Your Profile
This method removes the data file from Outlook’s profile so it won’t load anymore. The actual file stays on your hard drive, which is useful if you think you might need it later. Follow these steps carefully.
Step 1: Open Outlook Account Settings
- Open Outlook on your computer
- Click File in the top-left corner
- Select Account Settings from the dropdown menu
- Choose Account Settings again from the submenu
Step 2: Go To Data Files Tab
- In the Account Settings window, click the Data Files tab
- You’ll see a list of all data files currently attached to your profile
- Each entry shows the file name, type (PST or OST), location, and size
Step 3: Remove The Data File
- Select the data file you want to delete from the list
- Click the Remove button
- A warning message will appear telling you this removes the file from your profile but doesn’t delete it from your computer
- Click Yes to confirm
- Click OK to close Account Settings
That’s it. The data file is now removed from your Outlook profile. Restart Outlook to see the change take effect. If you later want to reattach the same file, you can use the Add button in the Data Files tab and browse to its location.
How To Permanently Delete An Outlook Data File
If you’re sure you no longer need the data, you can delete the actual PST or OST file from your computer. This frees up disk space and removes all traces of the data. But be careful—once deleted, recovery is difficult unless you have a backup.
Method 1: Delete Through File Explorer
- First, remove the data file from your Outlook profile using the steps above
- Close Outlook completely
- Open File Explorer and navigate to the default Outlook data file location:
- Windows 10/11:
C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook - Older Windows versions:
C:\Documents and Settings\[YourUsername]\Local Settings\Application Data\Microsoft\Outlook
- Windows 10/11:
- Look for files with .pst or .ost extensions
- Right-click the file you want to delete and select Delete
- Empty your Recycle Bin to permanently remove it
Method 2: Use The Mail Control Panel
- Open Control Panel on your Windows computer
- Set the view to Large icons or Small icons
- Click Mail (Microsoft Outlook)
- Click Show Profiles
- Select the profile containing the data file and click Properties
- Click Data Files
- Select the file and click Remove
- Close all windows and restart Outlook
- Then delete the physical file from File Explorer as shown above
How To Delete Outlook OST File Without Losing Server Data
OST files are cached copies of your Exchange or Microsoft 365 mailbox. Deleting them is safe because Outlook will recreate the file when you restart. This is a common troubleshooting step for synchronization issues.
Step 1: Close Outlook
Make sure Outlook is completely closed. Check Task Manager to ensure no Outlook processes are running in the background.
Step 2: Locate The OST File
Navigate to the default Outlook data folder: C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook. Look for a file with the .ost extension that matches your email address.
Step 3: Delete Or Rename The OST File
You can either delete the file or rename it (e.g., add .old to the end). Renaming is safer because you can revert if something goes wrong. Right-click the file and choose Delete or Rename.
Step 4: Restart Outlook
Open Outlook again. It will detect that the OST file is missing and automatically download a fresh copy from the server. This process can take a while depending on your mailbox size and internet speed.
How To Delete Outlook PST File Completely
PST files are personal storage tables used by POP3 and IMAP accounts. Deleting a PST file removes all the data stored locally, including emails, contacts, and calendar items that haven’t been synced to the server.
Step 1: Backup Important Data
Before deleting any PST file, export important emails or folders to a new PST file. Use Outlook’s Import/Export wizard to create a backup.
Step 2: Remove From Profile
Open Account Settings, go to the Data Files tab, select the PST file, and click Remove. This detaches it from Outlook.
Step 3: Delete The File
Navigate to the Outlook data folder and delete the .pst file. You can also use Windows Search to find all PST files on your system.
Step 4: Clean Up Registry Entries (Advanced)
If you want to remove all traces, you can delete registry entries related to the PST file. This is optional and recommended only for advanced users. Open Registry Editor (regedit) and navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\[Version]\Outlook\PST. Delete the relevant keys.
Common Mistakes When Deleting Outlook Data Files
- Deleting the file while Outlook is still running—always close Outlook first
- Forgetting to remove the file from the profile before deleting it physically
- Deleting the wrong file—check the file name and path carefully
- Not backing up important data before permanent deletion
- Deleting an OST file without understanding it will be recreated
- Assuming deletion frees up space immediately—empty the Recycle Bin
What Happens After You Delete An Outlook Data File
After removal, Outlook will no longer display the folders and items from that data file. If you deleted an OST file, Outlook will create a new one and sync your mailbox from the server. If you deleted a PST file, the data is gone permanently unless you have a backup.
Your email account settings remain intact. You won’t lose your account configuration, signatures, or rules. Only the locally stored data is affected. For IMAP and Exchange accounts, server data remains unchanged.
How To Recover A Deleted Outlook Data File
If you accidentally deleted a PST file and emptied the Recycle Bin, recovery is difficult but not impossible. You can try:
- Using file recovery software like Recuva or EaseUS Data Recovery
- Restoring from a Windows backup if you have one configured
- Checking if the file is still in the Recycle Bin
- Looking in the Outlook data folder for backup copies with .bak extension
For OST files, recovery isn’t necessary because Outlook will recreate them automatically. But if you need data from a deleted OST file, you’ll have to sync again from the server.
Alternative Methods To Manage Outlook Data Files
Instead of deleting, you might consider these options:
Archive Old Emails
Use Outlook’s AutoArchive feature to move old items to a separate PST file. This keeps your main data file small without losing anything.
Compact The Data File
Outlook data files can become bloated over time. Use the Compact Now option in Account Settings to reduce file size without deleting anything.
Export To A New PST File
Create a fresh PST file and export only the folders you need. Then delete the old, large PST file.
Use Online Archive
If you have a Microsoft 365 subscription, enable the online archive feature. This moves older emails to the cloud, reducing your local OST file size.
Frequently Asked Questions
Does Deleting An Outlook Data File Delete My Emails?
It depends. For PST files, yes, local emails are deleted permanently. For OST files, no, emails remain on the server and will sync again. Always check your account type before deleting.
Can I Delete An Outlook Data File While Outlook Is Open?
No. You must close Outlook completely before deleting the physical file. Removing it from the profile can be done while Outlook is open, but file deletion requires Outlook to be closed.
How Do I Find Where My Outlook Data Files Are Stored?
Open Outlook, go to File > Account Settings > Account Settings > Data Files tab. The location column shows the full path for each data file. You can also open the folder directly from there.
What’s The Difference Between Deleting A PST And An OST File?
Deleting a PST file removes your local data permanently. Deleting an OST file only removes the cached copy—Outlook will download a fresh copy from the server when you restart. OST files are for Exchange and Microsoft 365 accounts only.
Will Deleting An Outlook Data File Fix Performance Issues?
Often yes. Large or corrupted data files can slow down Outlook. Deleting or compacting them can improve performance. If the issue persists, try creating a new Outlook profile.
Final Tips For Managing Outlook Data Files
Always back up important PST files before deletion. Keep your Outlook data folder organized by regularly archiving old emails. Monitor file sizes—Outlook performs best when PST files are under 20 GB and OST files under 50 GB.
If you’re unsure about deleting a file, remove it from your profile first. You can always reattach it later if needed. For OST files, renaming instead of deleting gives you a safety net.
Remember that the exact steps may vary slightly depending on your Outlook version. The methods described here work for Outlook 2013, 2016, 2019, 2021, and Microsoft 365. If you’re using an older version, some menu options might be in different locations.
By following this guide on how to delete Outlook data file, you can clean up your Outlook profile, free up disk space, and resolve common issues without losing important data. Take it step by step, and you’ll have a leaner, faster Outlook in no time.