Step 1: Launch PST Password Remover
Download and install PST Password Remover as an administrator.
Step 2: Select Options
Then, click on the Select Files Button to add the Locked PST File.
Step 3: Choose PST File
Choose the PST file that you want to unlock.
Step 4: Click Unlock PST
Click on the Unlock PST Button and your PST will be unlocked.
Step 5: Set Password
Now, you can click on the Set Password Button to add a new password to the PST File.
Step 6: Enter Password
Enter the Password confirm, and click on OK.
Step 7: Lastly, Complete the Process
You will receive a confirmation when your PST file is locked again with your desired password.