Do you mean when you view the PDF the pages are blank?
Which version of InDesign?
Which operating system?
How are you exporting and viewing the PDF?
If you mean he .idlk file, that has noting to do with the PDF. InDesign creates a lock file each time a document is opened to prevent editing by multiple users simultaneously, and it has no content that is user accessible. Lock files should be deleted automatically when the document is closed.