If you are having problems to emulate Android using Mac OSX El Captain 10.11.6, may this can help you.
If when trying to run the emulation you got the following message:
Emulator: Sorry, "qemu-system-x86_64" can not be run on this version of macOS. Qt requires macOS 10.12.0 or later, you have macOS 10.11.6.
The solution can be to downgrade your emulator version to Android Emulator Version 28.0.25.
After download you should replace your current emulator with this one. The emulator for Android Studio generally is located on:
So you can just replace the files and restart your Android studio.