Outlook Data File Cannot Be Accessed? Here’s How To Fix It

Some users have encountered issues that relate to Outlook data files not being accessed. Outlook Data files (OST files) are essential files needed by Outlook to access your data offline. When you cannot access these data files, Outlook will fail to send or receive emails inside the program.

A range of errors can cause Outlook to come across this error. If you’re looking for a way around, we’ve got your back! This article discusses the causes and ways to solve Outlook Data File not being accessed, so keep reading!

Why Can I Not Access My OST Files?

The primary reason why you may be unable to access your OST files is because you’re dealing with missing or corrupt files. However, these are other factors you cannot rule out while dealing with this issue. You may want to skim over the list of causes we have mentioned below before jumping to the fixes so you can use the method more relevant to your issue:

  • Slow Internet Connection
  • File Location Changed
  • Corrupted OST file
  • Third-party Add-ins
  • Configuration of Outlook Profile
  • Inadequate Permissions
  • Error in Synchronization

How to Fix Outlook Data Files Cannot Be Accessed?

Depending on the cause of this issue, there are many solutions you can try on your own to solve this problem. In this section, we have listed the solutions you can try for each other issues we’ve mentioned in the section above.

Fix Network Connection

You could be dealing with a weak internet connection if you’re dealing with Outlook not being able to access your data file. When you have a weak connection, Outlook might fail to retrieve information from its server for email exchange.


If you’re using a router, you can first try restarting it. Turn off the router, then wait for about 10 seconds before turning it back on. If your internet is usually this slow, you may want to contact your Internet Service Provider (ISP) and switch to a better internet plan.


As this problem isn’t as uncommon, Microsoft has a repair tool for both OST and PST files. These files come with the Office program files, so you do not have to install them from elsewhere.

Before running the scan, you must be sure where your Outlook Data Files are. If you’re unsure about the location, follow these steps to locate your Outlook Data Files:

  1. Launch Outlook.
  2. From the homepage, head to Account Settings from the Info tab.
  3. Select Account Settings from the fly-out menu.
  4. Head to the Data Files tab.
  5. Check the location of your OST files next to your username. 

After knowing where your data files are located, you can perform the scan. Here are the steps you can follow to run the SCANPST.EXE file to repair Outlook Data Files:

  1. Open File explorer and navigate to C:\Program Files\Microsoft Office\root\Office16
  2. Select the SCANPST.EXE file.
  3. Browse to the location of your Outlook Data Files. 
  4. Click Start.
  5. If the wizard locates an error, select Repair.
  6. Restart Outlook.

Disable Third-party Add-ins

Certain third-party add-ins can be responsible for your Outlook program’s inability to access the data files. If you have a lot of add-ins added to your Outlook program, this is a solution method you should consider. 

If you have the time, you can disable each add-in and run Outlook, or you could disable all third-party add-ins and run Outlook to get the job done quicker. Here are the steps you can refer to disable Add-ins on MS Outlook:

  1. Launch Outlook.
  2. From the homepage, select Options from the sidebar.
  3. Select Add-ins from the window.
  4. Next to Manage, select COM Add-ins.
  5. Deselect the box next to third-party add-ins.
  6. Select OK.

Turn Off the Cache in MS Exchange

This method is if you’re using Outlook with a work or school email account. MS Exchange is the program responsible for providing you with your current email address. Sometimes, the cache build-up can create synchronization errors between Outlook and the Exchange program resulting in this issue.

You can turn off the cache in MS Exchange and try using Outlook again. Refer to the following steps if you wish to clear the cache in MS Exchange:

  1. Open Outlook.
  2. From the Info tab, select Account Settings > Account Settings.
  3. Double-click your user ID.
  4. Deselect the box next to Use Cached Exchange Mode.
  5. Select Next.
  6. Click OK on the confirmation box.
  7. Select Finish.

Change Data File Location

You may also encounter this error if your OST files’ location has been changed. When the location of your Outlook Data files gets changed, Outlook may not be able to access the data files for you to send or receive your email.

To solve this issue, you can change the location of your data file from the Outlook program itself. Here are the steps you can follow to change the data file:

  1. Launch Outlook.
  2. From the Info tab, head to Account Settings > Account Settings.
  3. Select Data Files tab.
  4. Select Add.
  5. Set a name and location, then click Ok.
  6. Select the new location and click Set as default.

Create New User Account

If none of the solutions apply, you can create a new user account. When you create a new user account, Outlook creates new data files for your new user account. Here are the steps you can follow to create a new user account on Outlook:

  1. Launch the Outlook program.
  2. Select Office Account from the sidebar.
  3. Select Switch Account > Add Account.
  4. Fill in the credentials for your new account or create a new account.

Repair Office

Your Office app may have gone corrupt if you cannot access the Outlook Data files. When a program file goes missing or corrupt, the Office app will have insufficient resources to follow the commands you request. If you wish to repair your Office program, follow these steps:

  1. Open the Settings app (Windows key + I).
  2. Head to Apps > Apps and features from the navigation panel to your left.
  3. Enter Office from the search bar.
  4. Click on the three-dot menu next to the program, then select Modify.
  5. Choose Repair from the dialog box.

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