How to Resolve “File access is denied” OST Error?

Microsoft Outlook is a globally popular email client. But, sometimes MS Outlook users get stuck and encountered various issues when users try to open the OST file. One such issue is getting “Outlook OST File access is denied” error.

I have recently found one such case where a user encounter the same error

Hi guys,

I have users with an additional mailbox attached to their profile.

When they try to access the mailbox items by starting MS Outlook and choosing the necessary profile they are presented with the following error:

File access is denied. You do not have permission required to access the file C:\…… \ – name.ost.
Are there any settings which could cause this? 

It halt Outlook working and can also could lead to permanent data loss. So, let’s try to learn some troubleshoots to fix MS Outlook errors and make it free from such issues.

How to fix “Outlook OST File access is denied .ost”

Fix 1. Uncheck ‘Read-only’ attribute – by disabling Read only option we can solve the issue

  1. Go to Control Panel and then in All control panel items choose the Mail option
  2. Then, select the Data files option, then select the OST file and click on Open file location
  3. After that, right-Click on the OST file and choose Properties
  4. Now uncheck the Read-Only Box and press on Apply and then hit OK

Fix 2. Run MS Outlook as an Admin– Running MS Outlook as administrator can resolve the error

  1. Right-click on Outlook icon application and select properties
  2. Then choose compatibility
  3. After that, mark “Run this program as an administrator” check box and press Ok

Fix 3. Change User Access Control Settings – Verify whether the user has full control permission

  1. Right-Click on the OST file and then visit Security tab under properties
  2. Now, click on the edit tab and Press on add tab
  3. In “user or group” window will, type everyone and select the check names button.
  4. Now, select everyone and press the full control tab, and finally press OK.

Fix 4. SCANOST.EXE (Integrity Check tool) – If you are still facing the same issue, this indicates that your OST file is corrupt. In such case Microsoft Outlook comes with an inbuilt diagnostic tool to repair files. It is the default repair tool for OST files. It diagnoses and repairs the OST file which is not working. This tool is apt for minor OST file recovery but if the issue is something bigger then perhaps the ScanOST will not work.

Now, in case the in-built app fails to fix corruption and can’t repair OST file. In such case, you can use OST to PST converter software to convert inaccessible/corrupted OST to Outlook importable PST format. An OST to PST conversion tool can fix any level of corruption. Also, it will help you to read an inaccessible OST file data without any loss.


It is very common to encounter the error message while using an emailing application like MS Outlook. Such error not just hampers the work but might also lead to data loss. Thus, using the above manual methods, one can resolve these issues effective. But, if a problem still occurs, go for an OST to PST converter is the most effective solution to solve any kind of OST file errors.

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