Install and run the Outlook Duplicate Remover Tool as an administrator on your PC.

In the opening wizard, you can view two options: Single File and Multiple Files/ Folder. Opt with one according to your requirements.

Here, I select the Multiple Files/Folder option to add multiple files and click on the Next button.

The next tab contains options like Select Files and Select Folder. Click one to select the PST files or Folder containing multiple PST files.

In the new window, you can find the tree structure containing folders of your selected PST files.

Check the folders from which you want to remove duplicate items.

You can also view the information of a specific folder, such as From, Subject, Date, and Attachments. Click Next.

Here, you can find the different inbuilt features like Mail Filter to separate the duplicates-removed emails on a specific date range and Task Filter to filter the tasks of PST files between the Start Date and End Date.

Now check the Mail, Calendar, Tasks, and Contact checkbox to remove duplicate items from them.

Opt for the Remove Attachments option to exclude the attachments files from the chosen folders.

Now, you can get two options to remove duplicate items from PST files Search duplicate items within the Folder to search duplicate items within the folder and Search Duplicate Across the PST Files to search similar items across the Outlook PST files.

Click this button to specify duplicate criteria and select task comparison criteria for Mail, Contact, Calendar, and Task.

In the opening wizard, select the task comparison criteria (Mail, Contact, Calendar, and Task) according to which you want to perform a comparison.

Choose the action from the drop-down you want to implement on the duplicate emails.

Moreover, if you select the Make a new folder option, assign the folder name.

After opting for all the required changes, click on the Save button.

Click on Path To Saves to select the destination path of new PST files and the Convert button to start the removal process of duplicate items from the selected PST files.

Here, you can also save the report of the conversion process by clicking on the Download Report button.