04-14-2012, 11:53 PM

I am trying to crop some pdf files. When I open the files, I get a window saying the file is locked. I then go to duplicate the file to create an unlocked version but I still can't crop the image. My questions are:
How do I keep files unlocked? Why is there a lock there in the first place?
How do I crop pdfs with Preview? Is there a step that I am missing?
Are there better programs for Macs that work with pdfs?
Thanks

04-15-2012, 01:17 AM

Some PDF files are locked. They're locked by their creator and can not be modified. What kind of PDF files are they that you're trying to modify? Note that even if you duplicate the original, it will remain locked.

04-16-2012, 03:55 PM

I scanned a flyer at work and then emailed it to myself at home. When I opened it at home it was locked. I didn't lock it when I orginally scanned it so I don't know how it got locked in the first place.

04-16-2012, 03:58 PM

It's very likely the flyer was already locked when you scanned it. Sending it to yourself via email has nothing to do with that.

04-16-2012, 04:00 PM

How would it be locked? It was a physical paper flyer that I put into my scanner to scan. Would my scanner have setting to lock/unlock scans?

04-16-2012, 09:08 PM

It was probably locked by its author. Whenever a PDF is created (using Adobe or other creation software) there is an option to lock the document so that others can not make changes to it. Very common procedure especially with copyrighted documents, graphics, etc.