Zotero 5 on Mac - After re-install I keep getting the message "There was an error starting Zotero"

I have installed Zotero 5.0.79 on my Mac with Sierra 10.12.6. After the install, I can't start up my Zotero - it keeps giving me the message that "There was an error starting Zotero" (more below). It gives me the option to "Quit" or "Check for Updates". Then, when I check for updates it says that no updates are available. The only option is to press "OK" which then shuts it down.

Any insights on how to fix this issue?

Cheers, Nathan

There was an error starting Zotero.

Error: Invalid field 'accessDate
From previous event:
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