Rebuild and Recover Damaged Offline OST File in Outlook

Updated On - November 12, 2023 by Nasir Khan |

Reading Time: 9 minutes

MS Outlook users are well-versed with OST and PST files. Like any other file format, corruption in OST files is a prevalent error. It can happen for many reasons, and reasons vary from user to user. Here in this blog, we will know the reasons and how to rebuild or recover damaged Offline OST files in Outlook. Read the blog till the end to get rid of corrupted OST files.

About Outlook OST File

Outlook Offline Storage Table (OST) files allow to work even when Offline.OST is a replica of the mailbox data stored on the Exchange server. OST file is created on the local machine when you configure or sign in using a Microsoft Exchange, Microsoft Office 365, or IMAP account in MS Outlook.

OST files let users access, read, and draft messages even when the system is offline. All the changes done offline are synchronized with the Exchange Server when the system is connected to the Internet.

Corrupt Outlook OST File Error Messages

In Microsoft Outlook 2013 or later versions, you receive the following error message:

Errors have been detected in the file C:\Users<name>\AppData\Local\Microsoft\Outlook\

Recover damaged OST files

Most Common Reasons for Outlook OST File Corruption:

Outlook OST files may get corrupted, damaged, or inaccessible for many reasons. The reason varies for each case. Some of the common reasons are listed below:

  • Improper application termination is a common reason behind the corruption of the OST file.
  • The presence of Viruses/Bugs in the system may also trigger the corruption in the OST file.
  • Hardware-related issues, Sudden Power failure.
  • Oversized or large OST file
  • Corruption or bad sectors in the hard disk where the OST file is saved
  • Incompatible third-party Outlook add-ins.
  • Network issues during mailbox synchronization
  • Header File Corruption
  • System crash
  • Disk errors
  • Force close ‘Not Responding’ MS Outlook
  • Internal structure issue
  • Data storage device failure
  • Corruption in the file system
  • Storage limitations
  • Accidental deletion of Exchange mailbox
  • Inefficient synchronization or incorrect file system recovery

Symptoms that indicate issues with Outlook OST File:

Below are a few common symptoms that indicate issues with Outlook OST files:

  • Outlook takes a long time to load/start. The process becomes very slow and time-consuming.
  • Delays in sending or receiving new emails while using Outlook.
  • Issues with mailbox synchronization.
  • Outlook crashes or freezes frequently.

Manual Methods to recover damaged offline OST File

1st method: Recreate OST File

  • Open Control Panel.
  • Select Mail Recreate OST File to recover damaged offline OST File
  • Click Show Profiles. step 3
  • Choose the profile name and click on Properties. step 4
  • Click Email Accounts. step 5
  • In Account Settings, select Data files, select the File Path.
  • Click Open File Location. step 7
  • Delete the corrupted OST File.

A new file with the data of damaged OST is created.

2nd method: Use the built-in Outlook Inbox Repair Tool

Use the scanpst.exe utility of Outlook to repair OST File.

  1. Run the exe from where Outlook is present.
  2. Click Browse to locate the corrupted OST file. Use Inbox Repair Tool to recover damaged offline OST File
  3. Click Start to begin repairing. step 3
  4. Once scanning is completed, click Repair. step 4
  5. On completion of repair process, a Repair Complete dialogue box appears. step 5

3rd method: Launch Outlook in Safe Mode

Sometimes add-in can cause conflict. In safe mode they’re disabled. Use the command, outlook.exe/safe.

Launch Outlook in Safe Mode

4th method: Disable Firewall & Anti-virus settings to Repair OST File

Turn off the antivirus program and other firewall settings, as Outlook is programmed to scan and detects problems for every incoming and outgoing email. An enabled antivirus setting may sometimes block the normal working of MS Outlook, so you may need to disable the settings and restart the system to view the changes.

5th method: Update Folder

This manual method allows changing the properties of the folder (to clear offline items) to repair corrupt, damaged or inaccessible Outlook OST File issues.

For MS Outlook 2010:

  1. Right-click the folder and click Properties.
  2. When the dialog box appears, click the ‘Clear Offline Items’ option.
  3. Click Ok.
  4. Click Send/Receive option in Outlook.
  5. Click Update Folder to save the changes.

6th method: Compress the OST file

A large-sized Outlook OST file may lead to OST file corruption, sluggish Outlook performance, etc. The OST file items are stored in such a way that they may occupy additional space and be unusable for other purposes. Compacting the OST files reduces the extra space occupied by the OST files.

Compress OST file

7th method: Turn-off Anti-Virus

Turning off anti-virus software helps in the proper functioning of MS Outlook. The user can disable settings and restart Outlook to see the changes.

8th method: Turn off Compatibility Mode

  1. Navigate to the Startmenu and type exein the search bar.
  2. Once opened, right-click on the outlook.exe and select Properties.
  3. Click on the compatibility tab and clear the command, i.e. ‘Run this program in compatibility mode for’ in the dialogue box.Click OK and restart your computer.Turn off Compatibility Mode

9th method: Set Outlook Profile via Auto Account Setup in Outlook

  1. Navigate to the Windows Control Panel and select Mail in options.
  2. In the dialog box that appears, select Show Profiles.
  3. In the next dialog box, click Add.
  4. Select New Profileand, select the account type (be it Exchange account), click OKto proceed.
  5. On the Auto Account Setuppage, enter your name, email id, and password linked to your mailbox.
  6. Click Next to continue.
  7. Outlook will start to configure your account. In the dialog box that appears, check the option ‘Don’task me about this website again’. Click Allow.
  8. A Windows security dialog box appears – enter your username along with the password. Click OK.
  9. Once done, Outlook will discover your email account and end the configuration process. Click Finish to end up configuration. And this is how you can recover damaged offline OST file

10th method: Recover Navigation Pane Configuration File

    1. Click on the Start menu.
    2. Select the Run command from the menu.
    3. Type the command i.e. outlook.exe /resetnavpane in the dialog box. Recover Navigation Pane Configuration File
    4. Click OK and restart your device.

11th method: Fix Outlook hanging on Loading Profile

Step 1: Ending all the processes working in the task manager

  1. Right-click on the taskbar and click on Task Manager.
  2. In the tab of Processes, select all the office processes working.
  3. For each process, click End Task and repeat it for every enlisted process.

Step 2: Disable all the outlook presence features

  1. Launch Outlook. In the main menu, select Files >click Options >click People.
  2. Uncheck all the checkboxes, i.e. display online status next to the name and show user photographs when available.
  3. After unchecking all boxes, click OK and restart the Outlook application.


Why Don’t Professionals Prefer Manual Ways?

Although manual methods come for free, they are not free from limitations and drawbacks. There are many reasons that discourage users from going with the manual ways. Some of them are:

  • The manual method of repairing damaged Outlook OST files only fixes minor errors.
  • There is no guarantee of data safety and chances of data loss.
  • The inbuilt tool is unavailable in Outlook 2010, 2013 or later versions.
  • There is a size limitation when recover damaged offline OST files using manual methods. The manual method supports repairing damaged OST files only up to 2 GB in size.
  • The process is technically enriched, and non-technical users need help executing the OST repairing process.
  • High risks of human errors as you have to follow many steps while processing.
  • The manual process of repairing damaged OST files is slow and very time-consuming. If you have many OST files, you must repeat the process individually.
  • The manual process cannot repair encrypted OST files.

Third-party Professional OST File Recovery Software

Regain OST Recovery tool is professional third-party software to recover corrupt, damaged or inaccessible Outlook OST files. The tool effectively recovers mailbox data from Outlook OST files and saves them in PST files. The tool recovers deleted emails, calendar events, contacts, notes, tasks, appointments, journals, etc., from OST files and allows saving the recovered data in PSTEMLMSG, MBOX, vCard, and HTML file formats.

Free Download100% Secure Buy NowPrice: $39

Some Prominent Features of Regain OST File Recovery Tool:

  • Regain OST File Recovery Tool allows exporting OST file to office 365 accounts or Live Exchange Server.
  • It is also capable of repairing password-protected OST files.
  • Displays preview of recovered email items before saving, so you can be assured of the recovered data when recover damaged offline OST file.
  • There is no file size limit to recover damaged OST files. The tool works on any large-sized with ease.
  • The tool properly maintains metadata, formatting, and structure of OST files. The folder hierarchy of the tool remains intact.
  • Offers an easy-to-use, self-descriptive graphical user interface. Any user with technical expertise can quickly recover their files.
  • It offers multiple file formats to save the data after recovery. You can save the data in EML, MSG, PST, MBOX, vCard, ICS and HTML.
  • Compatible with all versions of MS Outlook and Windows operating systems.
  • Available as a free-to-download demo version. Users can install and run the tool to get assured about the tool’s working.
  • Users also get free lifetime technical support along with the Regain OST File Recovery Tool when recover damaged offline OST file.

How does it Work?

The working of the software is effortless and straight. Users can easily recover recover damaged offline OST file by following the below-given steps:

  • Install and open the Regain OST File Recovery Tool.
  • Now, you will get a welcome screen displaying an option to add an OST file. Browse the OST file by using the given button.Regain OST Recovery tool to fix damaged offline OST File
  • The added file will be scanned.
  • You can easily see your OST data on the left pane. You can be assured about the data by previewing it before saving.Step 4
  • Now, you must select the destination and file format you want to save the data. Step 5
  • The saving process will start, and you will get the message as it completes.Step 6

Final Words:

This article discusses all aspects of inaccessible, corrupted OST files and their recovery. It starts with the reasons for corruption and the manual methods for repairing and recovering damaged, inaccessible or corrupt Outlook OST files. Since manual methods have limitations, we recommend using a professional third-party OST File Recovery tool to recover damaged offline OST file. Regain OST Recovery Tool is fully explained in this write-up. You can also check the tool’s capabilities by downloading a free trial version.

Frequently Asked Questions:

Q1. Will it maintain the folder hierarchy after the recovery and saving?

Yes. The Regain OST File Recovery Tool properly maintains the folder hierarchy and originality. You will get your data in the same manner as it was before the file corruption.

Q2. I am not technically sound and may need technical assistance with the OST recovery. Can we have some technical support with this utility?

Though the tool has a very user-friendly and straight GUI, Regain’s technical support team is always available to help you. If you still need any assistance. You can contact Regain’s technical team round the clock for any assistance with the software. Users get free technical support with the Regain OST File Recovery Tool.

Q3. I have multiple OST files, and I cannot assess them. I want to recover all OST files; is Regain’s OST recovery tool able to process multiple OST files?

Yes. The Regain OST File Recovery Tool can recover damaged offline OST file in multiple manner. You just have to purchase one license and process multiple OST files.

Q4. Will it also recover the contacts and calendars along with the emails?

It will recover all the items, including contacts, calendars, and emails.

Q5. How is the demo version different from the license version of Regain OST File Recovery Tool? 

The demo version is just a restricted version of the licensed version. It allows processing the 30 items per folder while there is n such restrictions with licensed one. In working both are same.

Author: Nasir Khan

I am Nasir Khan from India, working as a Content Developer in Regain Software. Here I am writing about our products and their updates. And writing some free solutions from converting emails or Cloud Migration process. We have tools like Email Converter, Emails backup and Cloud migration.

One thought on “Rebuild and Recover Damaged Offline OST File in Outlook”

  1. Avatar Michael says:

    From the very beginning, I knew that we could rebuild any damaged OST files. But what about recovering the vital data? This blog cleared up my total concept. Besides, thanks for the suggested software.

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