How to Fix OST Synchronization Error – Pro Tips

Rate this post

Summary:- Offline Outlook Data File (.ost) is the data storage file of Outlook to save data for offline access. It is used when you have an Exchange account and want to work offline or use or use the default Cached Exchange Mode. You can easily edit the data, save emails in the draft, and add and delete the data, but once you establish Exchange Server properly, all the offline work will be updated successfully. The same is true for the Exchange server and Outlook; the synchronization process between them is more straightforward and simpler. But sometimes, users report that due to inadequate network connection and hardware issues, they face the OST Synchronization Error and because of this, it is also possible that your OST file gets corrupted or damaged.

In this article, we discuss the multiple methods to fix OST synchronization errors and scenarios where users try to sync their Exchange server mailboxes with Outlook OST files and face the same synchronization issues. But What if this issue occurred due to the OST file corruption? In that case, you can use the OST File Repair Tool, which can completely fix all types of problems in the Offline data file(.ost).

OST Synchronization Error – Overview

This OST Synchronization Error occurs when you try to synchronize the OST file with the Exchange server mailbox and is also due to the OST file damage. Here, you may encounter an error message like: Outlook OST Synchronization error 8004011D-526-80040115-0. Thus, you won’t be able to send or receive emails due to this error. But before proceeding to the multiple fixes of OST Synchronization error, let’s look at a few common reasons behind Outlook OST synchronization error.

What are the Reasons Behind the Exchange OST Synchronization Errors?

There are several reasons which are responsible for the OST file synchronization error in Outlook 2003, 2007, 2010, 2013, 2016, and Outlook 2019. Some of the common are:

  • Network connectivity is the primary reason behind the syncing issue.
  • Due to the Cached Exchange Mode option being enabled, users may encounter the issue.
  • The issue also occurs when Outlook starts malfunctioning due to a problem in the local machine.
  • Not a proper update of MS Outlook is also a key reason behind the OST file synchronization error.
  • Corruption or damage of the Outlook offline data file(.ost) is also a prime cause.
  • Sometimes, OST synchronization occurs due to virus infection, sudden shutdown, and large size of OST.

Some Basic Troubleshooting Methods to check out the OST Synchronization Issue

There is no error in your OST file, but if you want to check the file for satisfaction, you can perform the steps below. This method worked in the different Outlook versions like 2010, 2007, and 2003.

  1. First, you must go to the mailbox folder that is not synchronizing.
  2. Right-click on it and select its properties.
  3. Here, you will find the synchronization tab.
  4. But if there is no synchronization tab, then you have not set up the folder for use in offline mode.
  5. And if there is a synchronization tab, check the multiple details like Last Synchronized on, server folder contains, and offline folder.
  6. Make sure that your Outlook and Exchange have a proper connection, and the folders are well synchronized; then, the server folder and the offline folder will have the exact details; otherwise, it would be different.

Follow the below steps to check for the automatic synchronization:

  1. Go to Tools and select Options.
  2. Here, in the Mail Setup tab, open the Send/Receive tab and enable the checkbox for Send immediately when connected.
  3. After that, click on the Send/Receive option.
  4. You must enable the automatic send/receive when the exciting option is clicked under the Send/Receive Groups dialogue box.
  5. Finally, click the OK button to finish the process.

Multiple Methods to Fix OST Synchronization Error

There are several methods to troubleshoot or resolve OST Synchronization issues in Outlook. Well, it has been seen that all the Outlook versions are affected by OST synchronization issues, like Outlook 2019, 2016, 2013, 2010, 2007, & 2003.

Method 1: Fix Offline Data file(.ost) Using the OST Integrity Check Tool

Scanost.exe, formerly known as the OST Integrity Check tool, supports Outlook 2003 and 2007 versions and allows users to fix minor corruption or damage to the OST file. But the matter of fact is that the utility does not work with the latest versions of Outlook.

Method 2: Check the Synchronization of Offline folders

This method helps you to verify that your OST files are correctly synced or not at the folder level. However, when you face synchronization issues with specific folders, use these procedures:

  • Firstly, right-click on the OST folder and click Properties.
  • Now, click on the Clear Offline Items and tap OK.
  • Finally, click on the Update Folder option in the Send/Receive tab.

Method 3: Fix OST File Synchronization Error Using the Inbox Repair tool

Sometimes, users face OST synchronization errors due to the corruption or damage of the file. Thus, you can also use the Inbox Repair Tool (scanpst.exe), which allows you to scan and repair damaged OST files. Follow the steps below to resolve the OST Synchronization issues:

  • Go to the Microsoft Office program file’s default location, search the Scanpst.exe application, and run it.
  • The software tab pop-up on your screen.
  • Click on Browse to select the corrupted .ost file.
  • Once added, tap the Start button to initiate the scanning process.
  • Make sure to check the backup of the scanned file before repairing it.
  • If there is an issue with your OST file, click on the Repair button.
  • Lastly, you will find a pop-up: Repair Completed.

Method 4: Rebuild a New OST File and Synchronize File

If you are still facing issues in managing the OST file, then try to rename your affected OST file and let Exchange rebuild the OST file. Follow the steps to create a new OST file:

  1. First, close the Outlook application.
  2. Then go to the location: – C:\Users\administrator\AppData\Local\Microsoft\Outlook
  3. Here, find the OST file and rename it.
  4. Restart Outlook, and try to synchronize the mailbox again.

After synchronization, repairing and rebuilding your Offline Outlook data file(.ost), if the OST Synchronization error may not be fixed yet, then you need to use the OST Recovery Software by DRS Softech, which will help you to fix all types of OST file error. The software is competent enough to instantly fix the OST file synchronization error and allows you to restore all the mailbox items from the OST file into multiple formats like PST, EML, MSG, DBX, and MBOX.

Know- How to Repair the Offline Outlook Data File(.ost)

Simple steps to recover data from the corrupt OST file:

  1. Download and install the OST Repair Tool as administrator.
  2. Click the Open button to browse the OST file.
  3. Select the recovery mode from the drop-down list and click Ok.
  4. The software scans your added files and shows you the recovered data.
  5. Check the folder in the preview panel that you want to restore.
  6. Click the Save button and select the saving format, either PST, EML or others.
  7. Turn on the other built-in features and click Ok to start the process.
  8. Here, your OST Synchronization Error gets resolved successfully.

The above-mentioned steps fix the OST Synchronization Error of the Outlook Offline data file. Still, if you do not want to put your mailbox data into the OST file, then you can also convert the OST file into PST format using the DRS OST to PST Converter, which allows users to convert multiple OST files into PST format.


Hopefully, after reading this blog, you can efficiently perform the OST file synchronization between the Exchange server and Outlook. Here, we discussed the multiple methods to fix the OST synchronization error when you face a syncing issue in an OST file. Additionally, we also suggest you the two best third-party solutions for OST file recovery and conversion.

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *