There will be shortcuts to aiStarter from your Desktop, Start menu, All Programs and from Stratup Folder (Windows only). The aiStarter program was installed when you installed the App Inventor Setup package. This program is the helper that permits the browser to communicate with the emulator. The emulator requires the use of a program named aiStarter.
You can check whether your computer is running the latest version of the software by visiting the page App Inventor 2 Connection Test. Important: If you are updating a previous installation of the App Inventor software, see How to update the App Inventor Software. Follow the instructions below for your operating system, then come back to this page to move on to starting the emulator
To use the emulator, you will first need to first install some software on your computer (this is not required for the wifi solution). Some schools and after-school programs develop primarily on emulators and provide a few Androids for final testing. So you can test your apps on an emulator and still distribute the app to others, even through the Play Store. App Inventor provides an Android emulator, which works just like an Android but appears on your computer screen. If you do not have an Android phone or tablet, you can still build apps with App Inventor.
