Cannot open files from iCloud drive on Mac but they open on iOS devices I only use iCloud Drive for files I need to access on my Mac and my iPad. I have a few Keynote presentations that open fine on my iPad and iPhone, but when I try ot open them on my Mac, I get an error saying that the file could not be opened. The error is the same for MindNode files as well. 

The error message simply says that it "Cannot open" the file. There is nothing else in the message.

I tried to logout and log back into my iCloud account, but that did not work.

Any suggestions how I can access these files on my Mac again?
Had this issue - 
Opened System Preferences - iCloud - UNselect iCloud Drive (confirm removing local files) - reboot.
Login again - do the reverse:  System Pref - iCloud - Select iCloud Drive.
Have a touch of patiences when you try to open files as that takes a few minutes to get everything back in order.
Worked perfectly for me.