You can use PDFCreator:
works on Windows 10, Windows 8, Windows 7 SP1
To batch unlock PDF files to make them OCRable in Acrobat, batch print them via PDFCreator. To batch print in PDFCreator, see https://www.pdfforge.org/tips/auto-save
Tested with PDFCreator 4.1.2 on Windows 7 SP1 x64 Ultimate.
Note that by default PDFCreator comes with PDF ...