It is no longer required key.
New Google Earth have some deleted features, and inputing key is one of them.
“Yep it’s free. But it is NOT the GEPro that folks used to pay for. There is very little useful difference between this new free version of GEPro and the “plain vanilla” free version of GE. They have removed so many features that calling what they are offering now GEPro is like calling a VW a Porsche. For example, try to open the parcel layer in the new GE “Pro” version, go ahead, we’ll wait ………………………………………………………………………………………………………………………………………………….. still waiting ………………………………………………………………………………………………………………………………………………………………………………………………………………………………..Okay so by now you’ve figured out, itis no longer offered with GEPro. The single most popular feature is just gone. And not gone for free, just gone entirely. No way to add it back in or anything. IOW GEPro is not really GEPro anymore. It’s just plain old GE with some new pretty much useless features. Typical Google BS.”