Basic Reinstall: Uninstall Roblox through your control panel (or Apps settings) and then download and install a fresh copy from the Roblox website. This is your first line of defense.

A doozy of an error, but not unfixable!

To fix An error occurred while starting Roblox Studio, Studio details failed to create key or deploy, Reset your Router, Reset TCP-IP, Disable proxy settings, etc.