For others who might be having this same issue with a different root cause, I found that somehow my
com.apple.smbd.plist file had gotten corrupt.
You can check this with
It should appear to be plain text, but if you see a bunch of weird characters, it's probably corrupt.
I simply deleted the file [and after realizing it did not get recreated on reboot] copied my
com.apple.smbd.plist from another Mac into
/System/Library/LaunchDaemons/. Then I checked the checkbox (or alternately, you could run
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.smbd.plist), and then rebooted.
Problem solved. Same issue, different root cause.
Edit: You should also verify permissions on
com.apple.AppleFileServer.plist, especially if copying from a different computer. I discovered that my
com.apple.AppleFileSharing.plist file had
777 permission, which was causing it not to load.
Ownership should be
root:wheel, and permissions should be
sudo chown root:wheel /System/Library/LaunchDaemons/com.apple.smbd.plist
sudo chown root:wheel /System/Library/LaunchDaemons/com.apple.AppleFileServer.plist
sudo chmod 644 /System/Library/LaunchDaemons/com.apple.smbd.plist
sudo chmod 644 /System/Library/LaunchDaemons/com.apple.AppleFileServer.plist