Mixpanel error: "mixpanel" object not initialized [duplicate]
If you are not using mixpanel in your code, you should check whether it is one of your extensions.
In my case it was the PageRuler extension and started happening only today.
Check your extensions, for me it was 'Page Ruler'
["https://chrome.google.com/webstore/detail/page-ruler/jlpkojjdgbllmedoapgfodplfhcbnbpn?hl=nl"] that caused this error.
Disable all extensions until the error does not occur anymore.