Savvy Ways to Fix “Outlook.pst Was Not Cleanly Closed By The Last Program”

admin | Modified: 2020-07-21T19:24:40+05:30 | Outlook

Have you ever receive this error “Outlook.pst was not cleanly closed by the last program” error while working with Outlook? And looking for the solution to fix the issue? If yes then read this blog, here in this article, we are going to discuss the methods to fix this issue.

Sometimes, the Outlook user profile becomes inaccessible due to the Outlook error: “Outlook PST was not cleanly closed by the last program that used it.”.

Remember, maintenance of Outlook email application is required because sometimes minor faults are responsible for Outlook data file corruption. Once the PST file got corrupted you have to repair that file to access data.

Let’s know some possible causes due to which ‘Outlook PST was not cleanly closed by the last program error occur.

Why the “Outlook.pst was not cleanly closed by the last program” Error Occurs?

Abrupt System Shutdown – When the system shuts down in an abrupt manner either because of power failure or forced closure even before the termination of all application.

Inappropriate Add ins – Third-party products try to plug additional add-ins in the Microsoft email client profile for enhancing the overall user experience. Sometimes the defective add-ins could become one of the reasons for the error caused.

Presence of Corruption – When the Outlook PST file is corrupted then there are chances of Outlook being crashed. This makes the database file inaccessible and restricts end users from performing their intended operation.

Virus or Malicious Attack – Any malicious product or virus attack makes the Outlook profile inaccessible and causes an error to stop clients from doing their work.

Due to any of the above reasons, users are unable to access their Outlook profile. It is important to do proper maintenance and analyze the Outlook PST files to work without any interruption.

How to Fix “Outlook.pst was not cleanly closed by the last program” Manually?

So, here we have mentioned some manual methodologies that can help users in resolving the Outlook data file .pst was not cleanly closed by the last program that used it issue.

Method 1: Compact the Outlook data file (.pst)

If you delete items from the PST file, it will automatically compact the current PST file and save the compressed file at an alternate location. It may help in resolving the Outlook error. You can start the compact process, by performing the below steps:

  1. Delete the items that you don’t want to keep and empty the Deleted Items folder.
  2. Click on the File >Account Settings>Account Settings.
  3. On the Data Files tab, click the data file that you want to compress, and then click Settings.
  4. Click on the Advanced tab >Outlook Data File Settings.
  5. In the Outlook Data File Settings dialog, click Compact Now and then hit OK.

Method 2: Archive or Clean Large PST Data

By archiving the mailbox items that includes data from all folders helps in reducing the size of the PST file. You can also cleanup your inbox and organize your emails by using the below steps:

  1. Run the Mailbox Cleanup tool.
  2. Click the File tab.
  3. Click Tools > Mailbox Cleanup.
  4. Select on the View Mailbox Size >> Find items older than >> Find items larger than >> View Deleted Items Size >> Empty Deleted Items folder
  5. View Conflicts Size or Empty Conflicts to perform your desired task.

Method 3: Repair file by using Scanpst.exe

In order to overcome the shortcomings of the manual techniques and fix “Outlook PST was not cleanly closed by the last program that used it” error easily.

We have an effective tool .i.e Outlook PST File Repair software, is an advanced tool that helps in repairing the damaged files. In the case of severely & highly corrupted PST files, the software provides the Advanced Scanning option to repair the highly corrupted files.

Moreover, the tool provides an option to split the large PST files, as they are more prone to corruption. This functionality helps to reduce further chances of corruption.

How to Repair the Severely Corrupt File Using Software?

Step 1: Download and launch the software.

Step 2: Click on the Add File button to insert the corrupted .pst files in the software.

Step 3: Now, choose the Quick or Advanced Scanning Mode to initiate the scanning procedure.

Step 4: After scanning PST, preview all desired items highlighted in the left panel of the software.

Step 5: Hit the Export button and access the recovered data successfully.


At the moment when “Outlook.pst was not cleanly closed by the last program” error occur in the MS Outlook application. It makes the PST file inaccessible to the users and may result in data loss. So, it becomes imperative to resolve the issue immediately.

Therefore, in the article we have mentioned both the manual and automated solutions to fix the issue. But manual method has certain limitations, sometimes they may not help in resolving the error in every instance. So, it is recommended to use an automated solution that gurantees the 100% resolution to fix the Outlook PST file errors.