Find out why your OST file can’t be opened!

Outlook may display an error message indicating that the OST file cannot be opened for several reasons. The OST (Offline Storage Table) file is used by Microsoft Outlook to store a copy of your mailbox data for offline access. Here are some common reasons and potential solutions for this issue:

1. Corruption of the OST File:
   • Solution: Use the built-in Inbox Repair Tool (ScanPST.exe) to repair the OST file. Alternatively, you can delete the OST file, and Outlook will recreate it when you restart the application.
2. Synchronization Issues:
   • Solution: Ensure you have a stable internet connection. You can also try to reset the OST file by closing Outlook, deleting the OST file from its location, and then restarting Outlook to allow it to rebuild the file.
3. Compatibility Problems:
   • Solution: Ensure that you are using a compatible version of Outlook. Sometimes issues arise after updates or when using incompatible add-ins. Check for and install any available updates for Outlook and disable any add-ins to see if that resolves the issue.
4. File Access Permissions:
   • Solution: Make sure you have the necessary permissions to access the OST file. Check the file properties and security settings to ensure you have full control over the file.
5. Profile Corruption:
   • Solution: Your Outlook profile might be corrupted. Try creating a new Outlook profile and configure it with your email account again.
6. Large File Size:
   • Solution: OST files can sometimes grow too large and cause problems. Consider archiving old emails and reducing the size of your mailbox. You can also compact the OST file to reduce its size.
7. Antivirus or Third-party Applications:
   • Solution: Sometimes antivirus software or other third-party applications can interfere with the OST file. Try temporarily disabling these applications to see if the problem persists.
8. Disk Issues:
   • Solution: Check the health of your hard drive. Bad sectors or other disk issues can cause problems with file access. Running a disk check can help identify and fix such problems.

Steps to Resolve OST File Cannot Be Opened Error

1. Locate the OST File:
   • The default location is usually: C:\Users\YourUsername\AppData\Local\Microsoft\Outlook\.
2. Delete the OST File:
   • Close Outlook.
   • Navigate to the OST file location and delete the file.
   • Restart Outlook to allow it to rebuild the OST file.
3. Repair Outlook Profile:
   • Go to Control Panel > Mail > Show Profiles.
   • Select your profile and click on Properties.
   • Click on Data Files and then Open File Location to find the OST file.
   • If needed, delete the file and restart Outlook to rebuild it.
4. Use ScanPST.exe:
   • Locate the ScanPST.exe tool on your computer (usually found in the Office installation directory).
   • Run the tool and follow the prompts to repair your OST file.
5. Disable Add-ins:
   • Open Outlook in Safe Mode by holding the Ctrl key while clicking the Outlook icon.
   • Go to File > Options > Add-ins.
   • Disable all add-ins and restart Outlook to see if the problem persists.
6. Check Disk for Errors:
   • Open Command Prompt as Administrator.
   • Run chkdsk /f and follow the prompts to check and repair disk errors.

By following these steps, you should be able to resolve most issues related to the OST file not being opened in Outlook.