I have installed Android Studio 3.3.1
and everything worked perfectly until I closed it. When I try to open a run again my project it says:
Intel HAXM is required to run this AVD
Unknown error, What should I do?
When Android Studio is open, click Configure on lower right corner, then select SDK Manager from the list. Head over to SDK Tools
Look for Intel HAXM and make sure it's checked. If not, check the box and click apply.
And you are good to go.
Make sure it is installed along with the Android Emulator. Then it should work.