Hello there, @tellis7171.

I can help you clear the closing dates and passwords in your QuickBooks for Mac 2016. 

Setting up, modifying or clearing the Closing date feature requires you to log in as an Admin and enter the password. Most likely you're using the limited user access. That's why you're unable to select the "Set Closing Date" button.

To clear the closing date, you will have to contact your previous bookkeeper to get the password. After that, clear the closing date and password set in QuickBooks.

For additional reference about QB for Mac, you can refer to this manual.

That's it. Let me know if there's anything else you need about QuickBooks. I'm always here to offer more help. Have a good one!