Thanks Alex and Esmi. I was able to rename the w3 total cache plugin and it allowed me to access the dashboard. Then I tried activating the lpugin again and it caused a fatal error. So then I removed the w3 total cache plugin and 4 caching files. The error went away.
I tried to redownload the w3 total cache plugin after removing the old files and it failed.
I now see that w3 total cache is untested with version 4.7 and there are similar problems being reported in their user threads. I still need caching, but don’t want to recreate problems.
any advice?