Windows 10 64-bit. Latest Acrobat Pro DC. Every restart (or Acrobat update) it keeps calling up the window to change the file type association for PDF to Acrobat, when it is ALREADY set as Acrobat, and will not clear itself out of the way (other than to X out of the window). There is no reason the 'change file type associate should be coming up if it is already set properly, both in file extension properties and in the registry.