'func' is not recognized as an internal or external command

I've noticed this error a few times in the past when running Azure functions locally. I can't remember the cause of each time, but the last one happened after a minor Node version upgrade, and using NVM to switch the latest version.

Basically, reinstalling the tools resolved it.

npm uninstall --global azure-functions-core-tools

then

npm install --global azure-functions-core-tools