Alternatively, if your PDF reader has a “Recently Viewed” tab, you can check there to see if the PDF you need is displayed.

You may have to select a new directory (e. g. , Desktop or Documents) first to locate the PDF in question. Alternatively, you can open a PDF by double-clicking the file. If this doesn’t open the file in Acrobat Pro, right-click the file and click Open with. . . Then click Adobe Acrobat Pro.

If you don’t know the user password, you cannot unlock the PDF.

You cannot unlock a PDF file if you do not know the password.