When an accountant emails you a secure PDF tax document, they frequently lock it with a complex 16-character password to prevent unauthorized interception. While this is excellent for initial transit security, it becomes incredibly annoying when you try to open the document six months later from your own secure hard drive and are forced to dig through old emails to find the password. You do not need to purchase an expensive Adobe Acrobat Pro subscription to permanently strip the encryption from the file. You can use the native macOS Preview application to instantly unlock the PDF and save an unencrypted copy.
How to Strip the Encryption
To remove the password from a PDF, you must know the password currently. The macOS Preview app is not a hacking tool; it cannot brute-force crack an unknown password. It simply allows an authorized user to remove the lock.
- Double-click the encrypted PDF file to open it in the Preview application.
- The screen will be completely black, and a prompt will demand the password. Type the exact password and press Enter.
- Once the document successfully decrypts and the text becomes visible on your screen, look at the main menu bar at the absolute top of your Mac.
- Click File, and select Export as PDF from the drop-down list. (Do not select “Export” or “Save”; you must select “Export as PDF”).
A standard save dialogue box will appear. Give the file a brand new name (e.g., “Tax_Document_UNLOCKED.pdf”). Do not click the “Show Details” button and do not check the “Encrypt” box. Simply click Save.
Why This Method Works
When you use the “Export as PDF” engine, the macOS Quartz system mathematically rebuilds the entire document from scratch based on the decrypted data currently loaded in your RAM. Because you explicitly chose not to check the “Encrypt” box during the export process, Quartz deliberately omits the encryption algorithms from the final compiled file.
The resulting Tax_Document_UNLOCKED.pdf is a perfect, 1-to-1 visual clone of the original document, but the 128-bit AES encryption wrapper has been permanently destroyed. You can now open the document instantly without ever typing a password again.