Outlook Error ‘Outlook PST in use and cannot be accessed’ – Solved!

As Outlook users would be aware, all their mailbox data on local machines in stored within a file known as Personal Storage Table (PST) file. This file is damaged/corrupted has the ability to make Outlook inaccessible for you. That’s the primary reason why each Outlook user should not only know about the PST, but also know how to deal with associated issues.

In this article we will be focusing on a specific problem scenario caused due to PST file corruption resulting in the error message, “Outlook data file cannot be accessed”. We will also talk about how to handle this issue and perform Outlook PST repair.

Problem Scenario

A number of Outlook users post queries on technical forums stating that Outlook crashes suddenly while working and when they try to relaunch it, the following error message appears:

The file C:\Users\user name\AppData\Local\Microsoft\user name\username.pst is in use and cannot be accessed. Close any application that is using this file, and then try again. You might need to restart your computer.

While for some users, restarting may solve the problem, for some it may not. Moreover, all users might not afford to restart their machine at the time owing to other important applications running. In such a case, what should a user do?

Understanding the Problem

Before moving on to the solution to this problem, it would be a good idea to know why it occurs in the first place. This knowledge will help you prevent the problem from happening again.

The error mentioned above occurs due to corruption in the Outlook PST file. And the major reasons behind PST file corruption include:

• Sudden loss of power when user is accessing mails or other mailbox items
• Application malfunction
• Virus infection in the PST
• PST file size exceeding its maximum size limit

All the above-mentioned causes for PST corruption are quite avoidable. If you have proper anti-virus installed and you take care not to download attachments from suspicious senders, you can avoid virus infections to the PST. With a UPS (Uninterrupted Power Supply) you can make sure your computer doesn’t shut down abruptly due to power loss. And when both these aspects are taken care of, application malfunction can be highly minimized.

As far as PST exceeding its size limit is concerned, that is totally up to you. If you keep your Outlook mailbox healthy by frequently deleted old and unused emails, attachments, notes, journal entries etc. and engage in regular mail archiving, you should be able to defer this problem.

However, in large organizations where thousands of emails are exchanged frequently and people don’t have the time to invest in cleaning up the mailbox, sometimes, a PST file corruption becomes unavoidable. So read the next sections to know how you can fix the issue.

Primary fixes you can try

Here are 3 great ways in which you can solve the “Outlook data file cannot be accessed” error:

1. Disable Cached Exchange Mode

Here are the steps:

• Quit Outlook if running.
• Open Control Panel and select Mail -> Email Accounts -> Email tab.
• Select and highlight the email address that gave you the error (username.pst) and then click on Change.
• Uncheck the option ‘Use Cached Exchange Mode’
• Click on Next -> Finish
• Restart Outlook

2. Kill All Outlook Related Processes

If the above method doesn’t work, try to end all processes related to MS Outlook. Here’s how:

• Open Task Manager by right clicking on the task bar and choosing Task Manager or simply pressing Ctrl + ALT + Delete on the keyboard.
• Choose the Processes tab.
• Select and quit any processes with names – “Communicator“, “Lync“, “ucmapi” or “Outlook“ by clicking on the process names and then clicking on ‘End Task’ button.
• Restart Outlook

Inbox Repair Utility (ScanPST.exe)

If none of the above methods work, you might need to repair errors within the PST. For this, you can use Microsoft’s inbuilt inbox repair utility called ScanPST.exe. Here are the steps:

• Quit Outlook if running
• Open Windows Explorer and navigate to MS Office installation folder (depending upon which version of Outlook you’re using)-

C:\Program Files\Microsoft Office\OFFICE12

• Locate and double click on ScanPST.exe
• Enter the name of the PST file you wish to check in the box ‘Enter the name of the file you want to scan’. Alternatively, click on Browse to select the file.
• Click Start
• If errors are found, you are prompted to start the repair process to fix the errors.
• Click
• Start Outlook with the profile that contains the PST file that you tried to repair.
• In the Navigation Pane, click Folder List. In the Folder List, you might see a folder named ‘Recovered Personal Folders’ that contains your default Outlook folders or a Lost and Found  The Lost and Found folder contains the folders and items recovered by ScanPST.

However, if none of the above-mentioned techniques seems to work, you should try using third-party software Stellar Repair for Outlook to repair the corrupted PST and recover all data within it. This reliable software repairs corrupted PST and restore all contents into a new importable PST file.