While you can't set a password for your entire Outlook program, you can set a password for an Outlook Data File (.pst). This password is required whenever you open the Outlook Data File (.pst).
But even Microsoft quote that: ‘If you set a password on your Outlook Data File (.pst) and forget the password, there is no way to retrieve the password’.
So, in short, there is no password recovery option and in that case, you are left with any professional password recovery tool.
This same situation happened to me as well and I also searched for many tools and at last, he got the most recommended tool from Microsoft MVPs i.e Stellar Password Recovery for Outlook the software generates six passwords that can be used to unlock password-protected PST and then reset the password again.#RationalApplicationDeveloper(RAD)#Support#SupportMigration