You can't unlock a PDF in Preview directly. Preview is a viewing and editing application, not a security tool. If a PDF is password-protected, you'll need to use a dedicated PDF unlocking tool or the original password to access the content.
Here are some common scenarios and solutions:
- Password-protected PDF: If you know the password, simply enter it when prompted. If you don't know the password, you can try using a password recovery tool, but these are often unreliable and may not work.
- Restricted PDF: If the PDF is restricted, you might be able to unlock it by changing the permissions. This can be done using other PDF editing software like Adobe Acrobat.
Remember, unlocking a PDF without proper authorization is illegal and unethical.
