Outlook is recognized as one of the most reliable email programs for personal and business communication. The user data mailboxes in Outlook is stored in 2 different formats; the Offline Storage Table (OST) and the Personal Storage Tables (PST). The OST files can be worked on offline, and when the user is back in the online state, the current email changes will synchronize with the Exchange Server. 

However, the user-created mailbox can still become damaged or inaccessible. The end result is missing emails, sync errors, or worse, complete data loss.
In this guide, we’ll explore the reasons behind mailbox damage, OST file errors, and the most effective and safest way to restore your mailbox data.

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Cause of Damage: OST file

Before repairing OST files, knowing the specific nature of the original problem would reduce the chances of repeating the same issues at a later time. The most popular cause is an Outlook or Windows crash. If you close or lose power to your computer or close or lose power to Outlook while using an OST file, the closing sequence may stop the original dialogues and location structure within the files, permanently altering the OST file. Following are a few other causes of damage to an OST file:

• Exchange Server Error or Disconnection: When Exchange Server shut down or interruptions in connection happens suddenly or without notice, it makes the OST file unsynchronized. This may bring about errors, or in some cases, make the file orphaned and inaccessible. 
• OST File Size Limitation: Each version of Outlook has a certain limitation for the size of the OST file. Upon reaching this size limit, if it’s a large mailbox, Outlook struggles to read or update the file and can become corrupt. 
• OST File Size Restriction: Every Outlook version has a limitation concerning the size of the OST file. If you hit that size limit, and it is a large mailbox, Outlook has difficulty reading or updating the file, causing Outlook to become corrupt.
• Faulty Updates of Outlook or Windows: There are instances where Outlook is updated incorrectly or incompletely, or Windows is updated incorrectly or incompletely and alters the way Outlook utilizes the OST files, leading to corruption or blocking access to the file.

Effective Methods to Repair and Restore OST File Data

When an OST file becomes damaged or corrupted, there are two reliable methods to repair it:
A manual repair method using Microsoft’s built-in tool, and an automated professional approach using specialized software.

Method 1: Fix OST File Using Microsoft ScanPST 

Microsoft provides a free built-in tool called ScanPST.exe (Inbox Repair Tool). It will help you to restore OST corruption and synchronization errors. It works well, but not for everyone, because those users who have technical knowledge or skill, novice users can't use it effectively like technical users. It works for minor damage, but when the mailbox is completely or highly damaged, it can't restore your data and might risk losing data.

Steps to Restore OST File Using ScanPST.exe:

• Close Microsoft Outlook completely.
• Locate ScanPST.exe on your computer (usually in the Microsoft Office folder).
• Launch the tool and click Browse to select your OST file.
• Click Start to scan the file for errors.
• After the scan, click Repair to begin fixing detected issues.
• Once the repair completes, reopen Outlook to verify the results.

Note: ScanPST works best for minor corruption only. It can take a long time to restore large files and may not recover all mailbox data.

Method 2: Advanced Way to Restore Mailbox OST File Professionally

If the manual solution does not help, using an external tool such as FixVare OST Converter is the next best option. 

This software can effectively repair and recover damaged OST files without losing your data. It will extract and recover your entire mailbox, including emails, contacts, attachments, and even calendars, with complete integrity. Not only does it keep your folder structure intact, it allows you to preview your mailbox before recovering or fully restoring an OST – and it can convert recovered data into many other formats for convenience and ease of backup or access.

Step-by-Step Process to Recover OST Data Using a Professional Tool

1. Download the mentioned tool.
2. Add the OST file you wish to repair or convert.
3. Preview mailbox data before starting the conversion.
4. Select export format (such as PST) and output folder.
5. Start the export process and wait until it completes.
6. Finally, open the file in Outlook to view the recovered mailbox items.

This method ensures a smooth and safe recovery process, even for users with no technical background.

Top Reasons to Choose a Professional Tool

The software has gained popularity not only for its ease of use but also its features and performance ensure trustworthiness among users. It restores damaged, orphaned or corrupted OST files in a quick manner and focuses on data integrity. An entire email profile can be quickly reconstructed without worry; each message, contact, or attachment will be reliable restored.

Some features that stand out include the fast processing of the files, secure data conversion, and viewing conversion before save. All of these features let the users verify data before exporting or saving. 

Some of the standout capabilities include faster file processing, secure data conversion, and preview before export, which help users verify their data before saving it.

• Here are a few more features that make this tool highly effective:
• Maintains complete data accuracy and folder hierarchy.
• Supports batch recovery of multiple OST files at once.
• Compatible with all Outlook and Windows versions.

In short, this tool is a perfect blend of simplicity and efficiency — offering both ease of use and advanced features to ensure smooth and safe OST file recovery every time.

Final Thoughts

To ensure continual operability and data safety, you need to fix the issues that occur in your Outlook OST files. The easiest way to fix an OST file issue manually is by using ScanPST.exe, but, for minor issues only. However, if you have an issue that's larger or more complex than the first part, the manual method may not work. 

Use an honest product, such as FixVare OST Converter, for the entire data recovery process and without loss of operational time. If users realize why the OST errors occur and which recovery solution to use, they will simply restore their Outlook mailbox data without interruption.