Outlook PST File Is Corrupted – How to Fix It Safely

If Outlook displays a message indicating that your PST file is corrupted, it means the internal data structure of the Personal Storage Table (PST) file has been damaged. Since Desktop Outlook depends entirely on PST files to store mailbox data, corruption can prevent access to emails, contacts, calendar entries, and attachments.

This guide explains why PST corruption occurs and how to fix it safely without risking permanent data loss.

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Common Error Messages Related to PST Corruption

• “The file xxxx.pst is not a Personal Folders file.”
• “Outlook data file cannot be accessed.”
• “Cannot start Microsoft Outlook.”
• “Errors have been detected in the file.”
• Outlook freezes or crashes while loading.

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Why PST Files Become Corrupted

PST corruption typically happens due to:

• Oversized PST file exceeding recommended limits
• Unexpected system shutdown
• Power failure while Outlook was running
• Hard disk read/write issues
• Malware or virus infection
• Improper PST file migration

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Method 1: Use Outlook Inbox Repair Tool (ScanPST)

Microsoft Outlook includes a built-in utility called ScanPST to repair minor file inconsistencies.

1. Close Outlook completely.
2. Locate ScanPST.exe on your computer.
3. Select the corrupted PST file.
4. Start the scan process.
5. If errors are found, choose Repair.

Important: ScanPST is effective only for minor corruption. It may fail when the file structure is severely damaged.

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Method 2: Create a New PST File and Reconnect Mailbox

If Outlook partially opens but behaves abnormally, creating a new PST file may help isolate corruption.

1. Open Outlook.
2. Go to File > Account Settings > Data Files.
3. Click Add to create a new PST file.
4. Set it as default.
5. Restart Outlook.

If accessible, manually copy data from the old PST into the new one.

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Method 3: Repair Severely Corrupted PST File

When Outlook cannot open the PST file at all, or ScanPST repeatedly fails, advanced recovery software is required to reconstruct the internal file structure.

The software provides:

• Deep structural scan of damaged PST files
• Recovery of emails, folders, contacts, and attachments
• Preservation of original mailbox hierarchy
• Preview before saving repaired data
• Support for all major Outlook versions

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How to Prevent PST File Corruption

• Keep PST size within safe limits
• Archive old emails regularly
• Avoid storing PST on external drives
• Close Outlook properly before shutdown
• Maintain system disk health

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Related Outlook Recovery Guides

• How to Recover Permanently Deleted Outlook Emails
• How to Repair Corrupted PST File in Outlook
• Outlook Not Opening PST File: Causes and Solutions
• How to Fix a Damaged PST File Without Using ScanPST
• How to Recover Deleted Outlook Folder

Conclusion

PST corruption can prevent Outlook from functioning properly. Start with the built-in Inbox Repair Tool for minor issues. For severe corruption, professional PST recovery software offers the safest and most reliable solution to restore data.