How to Resolve “Outlook Data File Access Denied OST” Issue?

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  • Updated on April 16th, 2024

Introduction: Has your Outlook stopped working? Are you unable to access emails and other mailbox data in Outlook? Well, this could be due to the Outlook Data File Access Denied OST error. Outlook users are generally troubled by errors and glitches. However, if you are also facing such an error, this blog has the solution. Let us discuss various methods to resolve the ‘Outlook OST file access is denied’ issue. However, irrespective of what is causing the error, you can use OST Converter to convert the inaccessible OST files. Further, import OST into your Outlook profile to fix the issue.

“Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. File access is denied. You do not have permission required to access the file.”

If you see, this kind of message while opening Outlook, this is an error- Outlook Data File Access Denied OST. This typically occurs when there are issues accessing or synchronizing the Outlook Data File (OST) with the Exchange Server. Such errors can be caused due to several reasons, as highlighted below.

Outlook OST File Cannot Be Opened- Causes

Basically, this error is caused when the OST File gets corrupted. So, here are the reasons causing the OST file to corrupt:

  • Exchange Server Connectivity Issues
  • Incorrectly relocated OST File
  • Interfering Anti-virus or Security Software
  • Outlook Profile Corruption
  • Access Permission Issues
  • Incompatible or faulty Add-ins
  • Sudden System Crash or Abrupt Shut Down.

Many times, the OST File Cannot be Opened Outlook error can be temporary due to poor connection or storage issues. However, whatever the cause is, we will discuss distinct methods to resolve this issue.

Ways to Resolve Error- Outlook Data File Access Denied OST

Listed below are different methods to resolve Outlook errors. Firstly, try to figure out the cause of the error and try the methods accordingly. Whether you use Outlook 2010, 2013, 2016, or 2019 on Windows, all these methods can be tried to fix the ‘Outlook OST file access is denied’ issue.

But before you begin with the main procedures to fix the issue, try the following measures:

  1. Restart System and Reopen Outlook
  2. Check proper internet connectivity

If the problem exists, apply the methods mentioned below, one after another.

Method 1: Ensure Windows is Updated and Restart

First of all, it’s important to ensure that the Windows operating system you are working on is fully updated. In some cases, if your Windows is not updated, it can be the cause of the issue.

To verify and install any available updates, follow these steps:

  • Firstly, open Settings on your system and select Windows Update.
  • Next, check if there are any pending updates, and proceed to install.
  • Once the updates are installed, restart your computer.
  • Finally, open Outlook again to check if the error has been resolved.

If the error ‘Outlook Data File Access Denied OST’ persists, proceed to the next method.

Method 2: By Changing Properties

Follow the given steps to change the properties of the OST Files.

  • Firstly, visit the control panel in your system. Press the Mail tab.
  • Next, click the Date Files tab. Choose the OST file from your system.
  • After selecting the OST file, click on the Open file location.
  • Press the right-click on the chosen OST file. Tap the Properties option. 
  • In the Properties section, check out all the details.
  • If the Read-only option is not applicable, apply it. Tap OK.

If the problem still exists, opt for the next method.

Method 3: Running Microsoft Outlook as an Administrator

Follow the below steps to run Outlook as an administrator and resolve your query:

  1. First of all, right-click on the Outlook application.
  2. From the options, choose Run as Administrator.
  3. After this, click Yes for verification.

Still, you’re unable to resolve the query “Microsoft Outlook OST file cannot be opened”. Try another method.

Method 4: Changes in UAC Settings

You can solve your issue by making changes in UAC (User Access Control) settings.

  • For the UAC changes, you need to right-click on the OST files. Tap Properties.
  • In the Properties option, select the Security>>Edit option. Press on the Add tab.
  • Once you tap the Add button, select the Users or Group option.
  • Next, enter everyone and then tap the check names button. Press OK.
  • After all the above steps, restart Outlook and check whether the issue is resolved. 

Thus, you can try another method for your query as well. However, in the next method, you need to create a different profile from the previous one.

Method 5: Generate Another Profile

To generate a new profile, follow the mentioned steps correctly.

  • Visit the Control Panel and tap on the Mail option.
  • In the Mail section, Choose the Show-Profiles button.
  • To add a new profile, tap on the Add option.
  • After adding your name, click on the OK button.
  • Next, enter all the correct credentials like your email address, name, etc. Press Next.
  • Restart your Outlook application and check whether the issue is solved or not.

After trying different methods, your OST File Cannot be Opened Outlook. You can try one of the most recommended processes which is using a professional tool.

Automated Method for Outlook Data File Access Denied OST

You can easily access OST offline on your system. However, there is a high chance of your OST file being damaged, corrupted, or any mishappening. To resolve your query, you can try the most preferable CloudMigration OST to PST Converter Tool method. If your OST File Cannot be Opened Outlook, you can use this wizard for the same.

Well, due to its simple navigation, users tend to opt for this tool. Apart from this, you can use this utility without technical knowledge. Besides, you can access them effortlessly on your system. Now, let’s discuss the steps the steps in detail.

Follow the Steps to Access the OST File on Outlook

If Outlook Data File Access Denied OST, follow these steps to access them with the tool:

  1. Download and launch the OST to PST Converter on your device.
  2. Add all the OST files that you want to access. Tap Open
  3. Now, you can preview all the selected OST files along with their attachments.

Thus, it also provides you the option to convert it into another file format or email client. For instance, you can Export OST to PST file format. You must be aware of the fact that the PST file format supports MS Outlook. As a result, it will be convenient for you.


In this blog, we provide different methods for the issue “Outlook Data File Access Denied OST.” You can try the free method to access the OST file. If they are unsuccessful, you can try for the third-party tool. Moreover, you can access it effortlessly in a snap.

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