Solved – OST File Cannot be Opened in MS Outlook 2016

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OST file cannot be opened is one of the most common issues among Outlook users. This usually happens during the Reinstalling and Upgradation process. In this blog, we provide you with the best solution to fix this problem. Also, we discuss the prime causes of the problem. So, let us begin.

OST files are also known as Offline Storage Table. As the name suggests these files are the Outlook data files that store a copy of all the online data in offline mode. This type of file will allow you to work even in the absence of a server connection.

Let us go through some of the most obvious and viable causes for the problem.

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Viable Reasons of OST File Cannot be Opened

There can be various reasons for a single problem in Outlook. Also, when we talk about Outlook data files, the number of causes is even greater. So, it is appropriate to consider the most obvious reasons for the problem. Below you will learn why Outlook cannot open OST files. Read them carefully.

  • It is also possible to experience many OST errors due to the synchronization of OST files and Exchange servers. So, we suggest you check the network connection properly.
  • OST files can become inaccessible if your hard drive contains bad sectors.
  • Use reliable antivirus software as sometimes Virus and malware attacks can also damage the OST files.
  • If we are working with the OST file and there is a sudden power failure, the file may get corrupted.
  • It is possible for OST files to become corrupt or inaccessible if the Outlook application terminates unexpectedly.

These are some of the most prominent reasons for the OST file issue. Mostly, the Outlook unable to open OST file problem gets resolved by considering these reasons and making suitable changes. Now, it is time to learn how to resolve the issue.

How To Resolve ‘OST File Cannot Be Opened’ Error Manually?

Majority of Outlook errors are fixed either by making suitable changes in the configuration settings or by repairing the corrupt Outlook data file. We will cover both the segments to resolve the issue.

Any approach to fix the problem that does not require any third-party application and consist of only DIY steps is known as Manual method. You can opt for this approach if you have a good understanding of the technical concepts.

There is a better alternative approach suitable for beginners and non-technical users. Automated or professional solutions are an advanced and effective way to solve your problem. We will discuss the professional tool later in this article.

Following are the most common techniques to perform when Outlook OST file cannot be opened Windows 10.

#1. Force Stop the Background Outlook Operations.

  • Go to your computer taskbar and right-click on it then select Task Manager or just press Ctrl+Shift+Esc to directly open the task manager.
  • Select the Details tab from the first row.
  • Now search names like Communicator, Lync, Outlook, or ucmapi and click on the End Task.

 After performing the above process still, your Microsoft Outlook OST cannot be opened then you can follow the below alternate method to solve the Error.

#2. Disable the Cached Exchange Mode From MS Outlook

As we mentioned above, when Outlook can’t open OST files, it may be possible someone tries to modify the OST file content. You can prevent unauthorized access to your precious data by disabling the cached Exchange mode.

It will break the connection between the email client and server. So, follow the below steps to disable Outlook cached Exchange Mode.

  • Go to the Control Panel.
  • Click on User Accounts to move forward.
  • Now, click on Mail(Microsoft Outlook) (32-bit).
  • Select the Email Accounts.
  • Then go to the Email tab.
  • Hit the Change

Note: Make sure that you have a Microsoft Account added to your Outlook otherwise unable to perform the below steps.

  • On the next page, you will find the Cached Exchange Mode option, disable the tick mark. Then click Next to proceed further.
  • In the last step click on the Finish
  • After performing the process, restart your system and try to access the OST file with it.

These two solutions will help you out if your OST file cannot be opened. But what would you do if the problem still remains?

What to Do if the Problem Still Persists?

If the file .ost cannot be opened because of inappropriate configuration settings, you can easily resolve them by performing the above two techniques. However, in case of data file corruption, these solutions will fail to serve the purpose. You need to repair the damaged file.

Based on the approach to fix the problem, there are two ways: Manual and Automated.

The former method will incorporate an inbuilt utility named as SCANPST.exe. It is located in the root folder of MS Outlook and able to repair minor corruptions. Let us see how to use the application when you cannot open OST file Outlook 2016 because of OST corruption.

  • Locate the scanpst.exe in the root folder of MS Outlook.
  • Double-click on it to run the application.
  • Now, browse the file and scan it for file corruption.
  • After that, click on the Repair button to resolve the file corruption.

The above steps will restore the Outlook OST file to its original state. However, as we mentioned above, this method is only suitable for minor corruptions. For a heavily corrupted file, you need to use professional software.

Advanced Tool fix the OST file cannot be opened Problem

DRS OST Recovery Tool is the most competent application to restore maximum possible data from a damaged Outlook file. It is a great alternative to the SCANPST.exe because using it you can repair even a heavily corrupted file. Also, the software is embedded with all latest and advanced features. Therefore, whether you are a novice user or an Outlook expert, this tool will prove to be beneficial for you.


In this blog, we have discussed why your OST file cannot be opened and how to access your mailbox data. We provide different techniques to resolve the problem based on different causes for the issue. However, if your Outlook data file has been corrupted and causes .ost cannot be opened error, using the DRS OST Recovery Tool is the best solution for you.

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