cannot access iCloud Account
When I click on iCloud from the Go menu or the sidebar, I am given the opportunity to upgrade to iCloud Drive. When I take that option, it opens my account where I can see all the information that I have already selected. When I click on Account Details, all the info is correct. Even so, I cannot access my files on my iCloud Drive.
Is it safe for me to Sign Out and sign back in again? Or should I try to delete Preference file first?
Mac Pro, OS X Yosemite (10.10.3), 14GB 800 mhz DDR2 FB-DIMM