Hello brainpop,
I apologize for the continued inconvenience this issue is causing. I have a few more questions that could help us to narrow in on what the issue may be.
Are you updating the Pro version from an older version of the plugin? If so, what was the last version of the plugin that you had active?
Also, where is the site hosted and what are the specs of the current hosting plan? With 43,000 events it could be causing some strain on the current hosting environment.
Hopefully the answers to these questions will help us to narrow in on the issue.
Thanks!