I find that occasionally adb loses touch with the fact that an emulator is running. I build my project only to get an error that adb timed out waiting for the emulator. I used to close the emulator, rebuild the project in Studio to relaunch the emulator, and wait, and wait. I discovered that you can restart adb without shutting down the emulator. That’s much faster.
As shown, open a terminal window and issue the adb kill-server command. Then, issue another adb command, such as adb-devices which will restart the adb server. From there, switch back to Titanium Studio and build your project for the emulator. This time, Studio will “see” the emulator, install, and launch your app.