Simple Guide to Repair Corrupt OST File in Outlook

Written By Md Shoaib
Updated on December 1st, 2025

Henry’s Query: “MS Outlook suddenly stopped working and kept showing errors like OST file cannot be opened. Maybe the OST file is damaged. How can I repair corrupt OST file without losing emails?”

Introduction: OST is an Outlook data file that stores a synchronized offline copy of your mailbox data from IMAP. It allows Outlook to work offline and sync changes once the internet connects. But when the OST becomes corrupted due to crashes or sudden shutdowns. Thus, Outlook may fail to open. This guide explains the simplest way to recover corrupt OST file manually. Also, explains the CloudMigration OST Recovery Tool to recover the OST file automatically.

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Table of Contents

Real-Life Scenario

A user faced the “Outlook data file cannot be opened” error while working on an important project. Therefore, Outlook kept crashing, and ScanPST couldn’t fix it. Using a CloudMigration OST repair tool, she repair corrupted Outlook OST files within minutes. This saves her from potential data loss.

Primary Reasons Behind OST File Corruption

Let’s discuss some of the common factors why OST files gets corrupted:

Sudden system shutdown or power failure.
Issues with Outlook synchronization.
Large-size or oversized OST file.
Malware attack or Windows corruption.
Hard drive failure or bad sectors.
Conflicts due to external installations.

Why Should You Repair Corrupt OST File?

The following factors highlight the need to recover a corrupted OST file:

Ensures the access to emails, contacts, and other mailbox data.
To prevent data loss from unsynced Outlook items.
This resolves Outlook errors caused by a damaged OST file.
Restores smooth offline access to mailbox data.
Also, avoids workflow disruptions due to unreadable OST files.
Moreover, recover data after crashes or improper shutdowns.

Step-by-Step Manual Process to Fix Corrupt OST File

This method involves using built-in Outlook utilities to repair common corruption issues. These help restore accessibility without depending on third-party tools.

Method 1. Use Outlook’s Built-in Repair (ScanOST/ScanPST)

Firstly, open SCANPST.EXE (Inbox Repair Tool).
Now, search the OST file.
After that, click Start to scan.
Click Repair if errors appear.
Lastly, restart Outlook.

Method 2. Recreate a File to Repair Corrupt OST File

Firstly, open Control Panel → Mail → Email Accounts.
Now, select your Account → Click Remove.
Re–add the account in MS Outlook.
Outlook will generate a new OST file automatically.

Difficulties Arise While Repairing The Corrupted OST File

This method works only if the OST corruption is minor.
It cannot repair severely damaged OST files.
Sometimes there might be a risk of losing unsynced mailbox data.
There is no preview option before repair.
Also, it is not suitable for batch OST repair.

Reliable Solution to Repair Outlook OST File

To get rid of the manual difficulties, using a CloudMigration OST Recovery Utility is the best solution. It helps users open OST file in Outlook to seamlessly recover the file. Therefore, this tool is designed with a user-friendly interface that is suitable even for non-tech users. Also, it recovers multiple OST files without any size limitations or other restrictions.

One-Time Service

If you don’t want to deal with software or technical steps, you can opt for a one-time OST repair service. Here, experts repair corrupt OST files with zero data loss. Moreover, this ensures:

100% Accuracy | Data Integrity | High-end Security

Procedure to Use the Software

Firstly, download and install the CloudMigration OST Recovery Tool.

Now, click Open → Add the corrupted OST file that you want to recover.

After that, expand the data structure → Preview the data from the file.

Lastly, choose any file format in which you want to save your corrupted file → Tap OK.

Top Benefits to Repair Corrupt OST File

This tool repairs extremely damaged OST files.
Restores emails, contacts, calendars, tasks, etc.
Recover inaccessible, encrypted, or oversized OST files.
Also, maintain folder hierarchy and metadata intact.
Moreover, this method ensures zero data loss, quick recovery, and complete file integrity.

Conclusion

To conclude, repairing a corrupt OST file is easy if you choose the right method. Manual fixes work for minor issues, but a professional OST repair tool is the only option for severe corruption. However, always keep frequent backups to avoid future data loss. The automated process ensures every detail is intact without any loss, with complete integrity. Moreover, this is the highly recommended software to repair corrupt OST file.

Frequently Asked Questions

Q1. How to repair corrupted OST files?

Ans. You can repair an OST file either manually or also, you can use a CloudMigration professional OST repair tool. This will automatically recover corrupt OST file with zero data loss.

Q2. Will repairing or recreating an OST file delete my emails?

Ans. No, emails stored on the server (Exchange/IMAP) will resync after rebuilding the OST. Only unsynced local data may be lost.

Q3. Can I convert a corrupt OST file to PST?

Ans. Yes, you can use the CloudMigration verified tool to fix corrupt OST file. Moreover, this supports the conversion even if the OST is damaged.

Q4. Which is the best tool to repair my corrupted OST file?

Ans. A dedicated OST Repair software is highly recommended to repair Outlook OST file. It recovers all mailbox items and handles severe corruption safely without any data loss.

About The Author:

Md Shoaib

Hi, I’m Md Shoaib! I enjoy writing about technologies and helping my readers with their queries, and I’m always looking for new ways to challenge myself and grow. Professionally, I work as a Digital Marketer, where I specialize in SEO and Copywriting.