Finally, I think I have got it. I reset the PRAM. EMC, checked the clock time and it was on time. But, then I changed the time to 2014 and back again. Hoping that it would work, I then erased the drive and upgraded to Sierra. It seems fine! My notifications flash in the upper right corner of my window, but I think that's due to the VPN I use. So, I shut notifications off. All is good for now. Thanks everyone!