Hi @farmgirlref, so sorry for the trouble here!
We believe we found the issue with the plugin directory name changes in our packaging system and have now resolved the issue.
I recommend to deactivate and delete the Events Calendar PRO and then update by getting the latest files from your account in theeventscalendar.com
https://theeventscalendar.com/my-account/downloads/
The process of deactivating and deleting the plugins does not change or delete events or settings, but it is always a good idea to have a backup.
Let us know if that helps get everything back to square one.
Thanks!
Geoff