Without the need of installing any password remover software. And it works fine even when the locked file disables you to select Export as PDF ...
This way works easily after the PDF file is unlocked.
Summary
- Open your PDF file with Preview
- Go to the status bar menu
File > Print...
or⌘ + P
- Click on the PDF button located at the middle bottom of the printer window
- Select
Save as PDF
Detailed
Open your PDF file with Preview
Go to the status bar menu File > Print ...
Click on the PDF button located at the middle bottom of the printer window
Select Save as PDF