Start by downloading the PST/OST Duplicate Remover and carry out the below steps. Step 1: Launch the toolkit and upload PST or OST Files. Step 2: Press the Next button and choose any files. Step 3: Select the mode of Outlook duplicate Item Removal. Step 4: Browse a location to store the output. Step 5: Press the Extract button to start the procedure. A log report with complete information and the folder will open up on the screen.