If you have already emptied the Recycle Bin (Windows) or Trash (Mac) after deleting the PDF files, they are no longer in the default recovery location. However, you may still have a chance to recover them using specialized data recovery software. Follow these steps: 1. Stop using the affected drive or storage device immediately to prevent overwriting the deleted files. 2. Download and install reputable data recovery software such as Recuva (Windows) or Disk Drill (Mac). 3. Launch the data recovery software and select the drive or storage device from which the PDF files were deleted. 4. Initiate a scan for deleted files. The software will search for recoverable data, including PDF files. 5. Once the scan is complete, preview the recovered files and select the PDF files you want to recover. 6. Choose a safe location on a different drive to restore the recovered PDF files to avoid overwriting them. 7. After the recovery process, verify that the recovered PDF files are intact and accessible.