How to Repair PST File in Outlook: Complete Guide [2025]

PST file corruption poses significant challenges for Outlook users, often leading to inaccessible emails and disrupted workflows. Understanding the root causes and preventive measures becomes crucial for maintaining data integrity.

1.1 Common Causes of PST File Corruption

Below are some of the common causes of PST file corruption:

Hardware failures rank among the primary triggers of PST file corruption. Bad sectors in hard drives can make stored PST files inaccessible. Additionally, network device problems, particularly when PST files reside on servers, can lead to corruption during remote access attempts.
Power-related issues significantly impact PST file stability. Sudden power outages or system crashes during active Outlook sessions leave ongoing processes incomplete, consequently damaging the file structure. Furthermore, software-related problems, including virus attacks and incorrect settings, contribute to file corruption.
Size limitations present another critical factor. Older versions of Outlook restrict PST files to 2GB, while newer versions support up to 50GB. Nevertheless, even with increased size limits, large files remain prone to corruption and performance issues.

1.2 Error Messages when PST file is Corrupt

Below are common error messages when a PST file is corrupt:

The file xxxx.pst is not a personal folders file.
The file xxxx.pst is not an Outlook data file (.pst).
Errors have been detected in the file xxxx.pst. Quit Outlook and all mail-enabled applications, and then use the Inbox repair tool(Scanpst.exe) to diagnose and repair errors in the file. For more information about the Inbox repair tool, see Help.
Microsoft Outlook has encountered a problem and needs to close.
Microsoft Outlook has stopped working
The set of folders cannot be opened.
The file xxxx.pst cannot be opened.
The path specified for the file xxxx.pst is not valid.
The Outlook data file xxxx.pst was not cleanly closed by the last program that used it. It cannot be opened until repaired.
A data file did not close properly the last time it was used and is being checked for problems.
xxxx.pst can not be accessed – 0x80040116.
Can’t move the items.
Cannot move the Items. The folder is full.
Note: An Oversized PST file or a file system limitation may also cause this error. In such cases, you may reduce the PST file size or change file system to fix it.
This Personal Folders file (.pst) is already in use in the current profile.
The file xxxx.pst cannot be found.
Something went wrong and your search couldn’t be completed.
An unknown error occurred, error code 0x80004001/0x800CCC0B/0x80070002.
“Not implemented” error when sending/receiving emails.
Error 0x80040119/0x8004011D/ox80004005/0x800CCC1A/0x800CCC92/0x800CCC0E/0X800CC0F/0x8004210A/0x800CCC13/0x8000FFFF when sending/receiving emails.
“421 Cannot connect to SMTP server” when sending/receiving emails.

1.3 Other Signs of PST File Corruption

Below are some other indicators that suggest PST file corruption:

0-size files
Some folders, emails, calendar events, or other items are missing.
Outlook slowdowns or doesn’t respond in many operations.
Outlook frequently crashes without apparent reasons.
Cannot receive emails

2. Free Outlook Built-in Options

Microsoft Outlook provides several free built-in tools to repair PST files, offering first-line defense against data corruption. These native options serve as immediate solutions before turning to third-party repair tools.

2.1 Scanpst.exe (Inbox Repair tool)

The Inbox Repair tool (Scanpst.exe) functions as Microsoft’s primary utility for diagnosing and repairing PST file errors. We have written a comprehensive guide on how to use this tool effectively (Microsoft’s official documentation is also available here).

2.2 Using the “Compact Now” Feature

The Compact Now feature can reduce file size and fix minor corruption by removing unused space. For more information, you can visit the official Microsoft page . Migrating PST data manually also has a similar effect as the “Compact Now” method, but it is much faster based on our tests, especially when the PST file size is large.

2.3 Using the “Import/Export” Tool

If the original PST is partially accessible, you can use the Import/Export wizard to extract recoverable data. For more information, you can visit the official Microsoft page .

2.4 Using the AutoArchive Feature

AutoArchive automatically manages mailbox size by moving older items to separate archive files. In some cases, this might help salvage data from a partially corrupted PST. For more information, you can visit the official Microsoft page .

2.5 Create a New PST File & Migrate Data Manually

If method 3.3 and 3.4 do not work, you can create a fresh PST file and migrate healthy data to it manually, which often resolves persistent corruption issues and repairs the PST file.

To implement this solution:

Select New Items > More Items > Outlook Data File
Assign a filename
Add password protection if needed

After creating the new file, transfer data through copy & paste or drag-and-drop. Importantly, this method allows selective data migration, helping eliminate corrupted elements from the transfer process.

Note: If you are unable to migrate the entire folder, some items in the folder may be corrupted. In this case, you can try migrating a subset of the items in the folder.

3. Fix Disk Errors Causing PST File Corruption

Disk-related issues often lead to PST file corruption. Sometimes, fixing disk errors can also repair the PST file.

3.1 CHKDSK

The Windows Check Disk (CHKDSK ) utility serves as a primary tool for identifying and fixing file system errors affecting PST files. This built-in command-line tool scans storage devices for bad sectors and structural inconsistencies.

After running CHKDSK, examine the PST file functionality in Outlook. Sometimes, multiple scan cycles might be necessary for thorough error resolution.

3.2 ScanDisk

ScanDisk is the predecessor of CHKDSK. It offers an alternative approach for addressing disk-related PST file issues. Unlike CHKDSK, ScanDisk provides a graphical interface, making it more accessible for users uncomfortable with command-line operations.

Both CHKDSK and ScanDisk work effectively alongside Outlook’s built-in repair tools. First, address disk-level issues through these utilities, then proceed with PST-specific repairs.

Common indicators suggesting disk-related PST corruption include:

Cyclic Redundancy Check (CRC) errors
Sudden file size changes
Unexpected Outlook crashes
Delayed file access
Error messages during email operations

For severe cases involving critical business data, consider these additional steps:

Create a backup copy of the PST file
Run disk diagnostics from the manufacturer’s utility
Check drive SMART status
Consider professional data recovery services

Remember that disk errors might affect multiple PST files simultaneously. Therefore, after resolving disk issues, verify all PST files stored on the affected drive.

4. Use MFCMAPI to Find Missing Emails

MFCMAPI is a free tool to access the internal data in a PST file. So you can try to use it to inspect the affected folder, and check if we can see and open the missing emails, as below:

Download the latest version of MFCMAPI .
Close Outlook completely, then open MFCMAPI.exe.
Click the Session option and select Logon.
Then hit OK after selecting your profile.
From the list, open a new window by double-clicking the messed-up PST file.
There a new window will open. Expand the Root Container and at the top of the Outlook data file click Inbox
Find and right-click the problem folder under Inbox, select Open contents table.
After opening that contents table section, in the new window, check if there are your emails in the upper part of the window
Finally, double-click an item to check if you can open the email in the Outlook window.

There is another tool called OutlookSpy that can do similar tasks, but it is not free.

5. Using DataNumen Outlook Repair to Repair Corrupted PST File

If all above methods fail or cannot recover your wanted emails, you can try professional tools such as DataNumen Outlook Repair, which offers powerful capabilities to fix corrupted PST files through multiple recovery methods. This specialized tool supports all versions of Outlook.

Free download

5.1 Repair a Single PST File

To repair a single corrupt Outlook PST file, please do as follows:

Close Microsoft Outlook and other applications that may modify your source Outlook file.
Select the source Outlook file (.pst).
If you know the version of Outlook creates the PST file, you can set it. Otherwise, DataNumen Outlook Repair will determine the file format automatically, increasing the whole repair time:
If the source file is Outlook.pst, the output file name will be set to Outlook_fixed.pst automatically. You can also change the output file name manually.
By default, the output file format is compatible with the Outlook installed on your local computer. If you want to use a different format, you can set it accordingly:
Click the “Start Repair” button
After the repair process, DataNumen Outlook Repair will output a new fixed Outlook file.

The repair process employs sophisticated algorithms to analyze every byte of the PST data file. Upon completion, the tool rebuilds the entire folder hierarchy, restoring emails and objects to their original locations. For lost and found items, they will be restored to specially designated folders named “Recovered_Groupxxx”.

5.2 Repair a Batch of PST Files

DataNumen Outlook Repair effectively handles multiple PST files through batch processing. This feature proves especially beneficial for organizations managing large email archives.

Below are the steps:

Go to the “Batch Repair” tab.
Click “Add Files” to add multiple PST files to be repaired.
You can also click “Search Files” to find files to be repaired on the local computer.
Click the “Start Repair” button
All the PST files in the list will be repaired one by one.

5.3 Recover from Hard Drive, Disk Image or Backup Files

Sometimes you may not have the PST file any more, for example:

You delete the PST file permanently.
You format the hard drive.
Hard drive failure.
The virtual disk in VMWare or Virtual PC is corrupt or damaged.
The backup file on the backup media is corrupt or damaged and you cannot restore the PST file from it.
The disk image file is corrupt or damaged and you cannot recover your PST file from it.

In the above cases, you may still be able to recover Outlook data from the hard drive, disk image or backup files directly.

If you have the disk image or backup files on hand, then you can do as follows:

Click “…” button to select the source file.
In the “Open File” dialog, select “All Files (*.*)” as the filter.
Select the disk image or backup file as the source file to be repaired.
Set the output fixed PST file name, such as E_Drive_fixed.pst.

If you want to recover from a hard drive directly, you can either use DataNumen Outlook Drive Recovery, or use DataNumen Disk Image to create a disk image file of the hard drive as the source file in DataNumen Outlook Repair:

Select the hard drive or disk.
Set the output image file name.
Click “Start Cloning” button to create the disk image file from the hard drive/disk.

5.4 Recover from Temporary Files

When Outlook accesses the PST file, it may create a hidden temporary file under the same folder as the PST file being accessed. For example, if the PST file being accessed is called MyOutlook.PST, then the hidden temporary PST file name will be MyOutlook.pst.tmp, created in the same folder as MyOutlook.PST.

When your Outlook is crashing and you cannot recover wanted data from MyOutlook.PST, then it is still possible to recover your data from MyOutlook.PST.tmp, as follows:

Since MyOutlook.pst.tmp is a hidden file, you must first change your system settings to show the hidden files .
Rename MyOutlook.PST.tmp to MyOutlookTmp.PST
Use DataNumen Outlook Repair to repair MyOutlookTmp.PST

5.5 Recover from Ransomware or Virus

If your files are compromised by ransomware or a virus, immediately create backups of the infected data.

Next, use DataNumen Outlook Repair to scan the infected files and attempt to recover your data. The software’s advanced scanning technology is specifically designed to minimize data loss caused by ransomware or virus-infected files.

5.6 Repair a Recovered File

If PST files recovered by DataNumen Data Recovery (or other data recovery tools) fail to open properly in Outlook, use DataNumen Outlook Repair to repair them and restore functionality. This tool specializes in addressing lingering corruption issues, ensuring repaired files become fully accessible in Outlook again.

5.7 Repair an Encrypted File

DataNumen Outlook Repair is also able to repair a password-protected PST file even if you forget the password. Just repair your encrypted PST file like a normal file and the output fixed PST file will not be encrypted any more.

6. Online Recovery Services

Online services offer convenient alternatives for repairing PST files without installing specialized software. These web-based solutions provide quick access to recovery tools through standard browsers.

6.1 Simple Recovery Procedures

Web-based PST repair services follow straightforward steps:

Upload the damaged PST file through an Internet connection.
Start the repair process and wait for it to complete.
Download the recovered file.

Most online services support PST files up to 10GB in size. After completion, users will see the recovery result immediately or receive email notifications about it. Furthermore, these services typically provide preview options, displaying folder structures and item counts before finalizing the repair.

6.2 Pros and Cons

Advantages:

No software installation required
Immediate access through web browsers
Support for multiple file formats besides PST
Automatic file deletion after 30 days for security
Preview capabilities before final recovery

Limitations:
File size restrictions often apply, with most services capping uploads at 2GB for standard versions. Additionally, many online tools cannot process password-protected files, except for specific Microsoft Outlook PST and OST formats.

6.3 Top Services

Recovery Toolbox stands among the leading online PST repair services. The platform supports various Outlook versions and provides comprehensive recovery options for emails, contacts, and calendar items.

7. More Solutions to Repair PST Files

Beyond the methods outlined above, numerous specialized Outlook PST repair tools exist to tackle complex corruption and recovery challenges in PST files. To simplify your search, we’ve compiled and rigorously evaluated the most effective solutions in a comprehensive list of top-tier Outlook recovery software.

8. Solutions to Resolve Other Outlook Errors

8.1 Determine Whether Your File is Corrupt

While file corruption is a common culprit, several other factors can also prevent Outlook files from opening properly, or cause other Outlook problems. These issues often generate error messages indistinguishable from those caused by actual file corruption.

To accurately diagnose whether corruption is the root problem, please do as follows:

Transfer your PST file to another computer with a functioning Outlook installation
Check and make sure it is not read-only by right-clicking the file and opening the Properties dialog.
Attempt to open the file in Outlook on the new computer.

If the file opens successfully on the alternative system, corruption can be ruled out and you don’t need to repair the PST file. The issue lies with your local computer settings rather than the file itself. Consider implementing the following targeted solutions to resolve the problem.

8.2 Possible Solutions

Repair Office
Create a new Outlook profile
Open Outlook in Safe Mode
Delete the original email account and create a new one
Disable some or all add-ins
Turn off antivirus tool, firewall and VPN
Restart your computer
Close all other applications
Copy the PST file to the local drive if it is stored on a network drive or mapped network drive
Verify the path of the PST file and fix it if needed
Check if the file is oversized
Check if the Internet connection is OK
Check Outlook profile settings
Check SMTP server settings. Change them if necessary.
Open or import the PST file with a higher version of Outlook
Delete Outlook cache files
Use an antivirus tool to check MSPST.dll and MSPST32.dll
Enable Cached Exchange Mode
Reset SRS file settings
Apply the latest Windows and Office updates
Change Junk Email Options to No Automatic Filtering
Disable Hardware Acceleration
Use System Restore in Windows to restore to the last successful launch point

You can also use command-line switches to reset or clear the various configurations of Outlook:

Use the Windows key + R to open the Run dialog.

In the Open box, input one of the following commands and press OK:

Command	Usage
Outlook /resetnavpane	Reset the Navigation Pane to fix UI-related issue
Outlook /resetfolders	Restore missing default folders
Outlook /cleanviews	Reset corrupted custom views
Outlook /restore	Restore to the profile and folders in the last success launch
Outlook /cleanprofile	Eliminate invalid profile keys and regenerate default registry keys where suitable
Outlook /cleanpst	Launch Outlook with a new clean PST file. After that, you can try to open the original PST file in Outlook.

9. Prevent PST File Corruption

Implementing the following preventive measures significantly reduces corruption risks and the necessity to repair PST files.

9.1 Maintain Optimal File Size

PST file size directly impacts both performance and corruption risk. Although modern Outlook versions support files up to 50GB, maintaining smaller file sizes proves essential for optimal operation. Best practices include:

Keep PST files under 10GB for optimal performance
Large files process operations slowly and increase corruption likelihood
Repair operations on oversized files become time-consuming, even for minor corruptions
Modern Outlook versions support multiple PST files simultaneously in the folder pane
Use Outlook rules to distribute emails across multiple PST files, reducing individual file sizes

For legacy format PST files (Outlook 2002 and earlier), strict size limitations apply. These older formats restrict PST files to 2GB maximum. When approaching this limit, users encounter various problems and increased corruption risks. Therefore, maintaining old-format PST files below 1.5GB constitutes essential practice.

9.2 Avoid Bulk Email Operations

Microsoft Outlook experiences performance issues when processing large email volumes simultaneously. The application may deadlock during mass operations, requiring forced shutdown and potentially corrupting the PST file. Operational guidelines:

Process no more than 10,000 emails in a single operation
When handling large email quantities, work in batches of 1,000 emails maximum
Repeat operations systematically until all emails are processed
This approach applies to select, move, copy, and delete operations

9.3 Store PST Files Locally Only

PST files function optimally when stored on local computer drives. Network storage introduces significant corruption risks that compromise file integrity. Critical storage requirements:

Never store PST files on network drives or servers
PST file architecture doesn’t support network environment access patterns
Network latency and connectivity issues trigger frequent corruption
Avoid sharing PST files across networks
Never allow multiple users simultaneous access to the same PST file via network
Concurrent network access substantially increases corruption probability

9.4 Close Outlook Properly

Abnormal Outlook shutdown represents a primary cause of PST file corruption. Users must ensure complete application closure before system shutdown. Verification procedures:

Never force-close Outlook through Task Manager during normal operation
Outlook continues background operations after window closure, including send/receive tasks
Check system tray for persistent Outlook icons indicating background processes
Open Task Manager and verify OUTLOOK.EXE absence in the Processes list
Sort the process list alphabetically for easier location

When Outlook persists indefinitely in memory, typically due to network communication issues, users can expedite closure by:

Manually disabling the network connection Outlook uses
Allowing connection timeout, which triggers background task abortion
Restarting Outlook, waiting several minutes, then exiting normally

9.5 Configure Antivirus Software Carefully

Some antivirus applications have been reported to damage or even delete PST files. Recommended precautions:

Configure antivirus software to exclude PST files from real-time scanning when possible
Monitor email operation performance when antivirus protection is active
Research antivirus software compatibility with Outlook before deployment
Be particularly cautious with aggressive security software that may quarantine or remove PST files

9.6 Manage Outlook Add-Ins

Incorrectly designed or malfunctioning Outlook add-ins contribute to PST file corruption. Management approach:

Regularly review installed Outlook add-ins
Disable unnecessary or rarely-used add-ins
If experiencing frequent PST corruption, systematically disable add-ins to identify problematic components
Test Outlook stability after disabling each add-in
Only retain essential, well-maintained add-ins from reputable developers

9.7 Implement Regular Backup Strategy

Regular backups constitute the ultimate safeguard against data loss. Backup best practices:

Schedule weekly PST file backups minimum
Store backups on separate physical drives or cloud storage
Verify backup integrity periodically
Maintain multiple backup versions for disaster recovery options
Test restore procedures to ensure backup viability
Document backup locations and restoration procedures

10. Conclusion

PST file corruption remains a significant challenge for Outlook users, though multiple effective solutions exist. Understanding prevention methods, particularly maintaining optimal file sizes and proper storage practices, helps minimize corruption risks. When corruption does occur, you can also use multiple solutions to repair PST file, below is a summary:

Microsoft’s built-in tools serve as first-line defenses against minor corruptions. Scanpst.exe, combined with regular maintenance through Compact Now and AutoArchive features, effectively handles basic repair needs. For severe corruption cases, DataNumen Outlook Repair tool offers advanced recovery capabilities to repair PST files, supporting both single and batch file processing across various Outlook versions.

Disk-level solutions through CHKDSK and ScanDisk address underlying storage issues that often trigger PST corruption. Additionally, online recovery services provide convenient alternatives when software installation proves impractical.

Remember, successful PST file management requires regular monitoring and proactive maintenance. Implementing these repair strategies while following recommended storage practices ensures your Outlook data remains secure and accessible.

About the Author

Xiu Xing is a seasoned IT professional with over 8 years of experience in enterprise email systems and Microsoft Office troubleshooting. He has helped thousands of users resolve complex Outlook issues across diverse corporate environments.

Xiu specializes in email system migrations, data recovery, and productivity software optimization. His hands-on experience includes managing Exchange Server deployments, troubleshooting MAPI connectivity issues, and implementing robust backup strategies for mission-critical email systems.

Through his technical writing, Xiu is committed to making complex IT solutions accessible to everyday users. He continuously stays current with the latest Office 365 and Exchange Online developments and emerging email technologies. When not solving email mysteries, Xiu enjoys sharing practical tech tips that help people work more efficiently.

Have questions about this guide or need additional help with Outlook issues? Xiu welcomes feedback and suggestions for improving these troubleshooting resources.