By opening with app command and by double clicking and by dragging. And yes, file associations are set to Acrobat DC as default. The app has been uninstalled and reinstalled. Computer has been rebooted. File permissions have been repaired. It was suggested by a chat representative that the operating system is too old. I'm on Mac 0S X 10.9.5 operating system, which I believe is Mavericks.
- This is a detailed troubleshooting document that may be useful.
That OS version is supported according to our system requirements document, but check for available updates for the OS.
I would definitely try updating Acrobat via Help>Check for Updates.
My other question would be does this happen with all PDF's or only certain ones? For example, can you open a PDF downloaded from adobe.com?
A test for an OS permissions issue would be to try with a new admin account.
Can you please try this:
Open a few files with Acrobat, go to Window -> Cascade -> Tile and see if that brings up the PDFs.
Also let us know if you are on a dual monitor system?