The problem was not my install. Even though I did a clean install and wiped out all my old SDK downloads, and so on with a Mac app called App Cleaner. (Yeah, I decided not to hunt through all the system files that I'd have to delete.) You can imagine my frustration at doing a clean install (deleting about 100 GB!), reinstalling, and creating a new AVD, and it STILL would not come up! GRRRR!!! Actually, more of a grr... *sigh*.
Last week when I was at the informal android meetup, I saved some terminal text. I found this:
"This AVD's configuration is missing a kernel file! Please ensure the file "kernel-ranchu" is in the same location as your system image." So I searched on that phrase, and found this website:
http://stackoverflow.com/questions/42659272/emulator-on-android-studio-doesnt-start-after-sdk-tools-update-to-25-3-1
I found this:
The problem is there are two emulators: one in $ANDROID_SDK_ROOT/tools, another one in$ANDROID_SDK_ROOT/emulator. The one in $ANDROID_SDK_ROOT/tools cannot start. Place $ANDROID_SDK_ROOT/emulator before $ANDROID_SDK_ROOT/tools in your $PATH variable, it should fix the problem. NOTE: For most Mac users, you can edit your ~/.bash_profile to change these settings and then run $source ~/.bash_profile to load the updates. In my particular case, I also had old values for $ANDROID_HOME that I had to clear out.
When I worked at RhoMobile, I edited for $PATH to add SDKs. A LOT! I hunted for my PATHs, and found in .bashrc (which my .bash_profile uses) a couple of $PATHs that edited for ANDROID_HOME. And for some old Android eclipse paths (yes, that is what I used to run Android at RhoMobile) that were way way way out of date, since Android Studio is not Eclipse. I commented them all out, restarted my Mac, started Android Studio, ran my latest AVD, and it came up. At long last. (I did not set any paths to emulator or tools.)
So if you have been walking the Android path a long time, and your AVDs will not start, look behind you. You might need to burn your old paths. Or at least comment them out.
As for me, I have a lot of old SDKs to reinstall. Not like I have not done that before. I can run them overnight.
P.S. I REALLY wanted my AVDs working. I start a tech writing gig at Google next week. (OH, YEAH!!!) Yes, Google gives its workers computers, and I will not be running any of their projects on my MacBook Pro. But it would be embarrassing to have no working AVDs on my MacBook Pro. Real Googlers would know. They always know.