I just installed Android Studios and trying to build my first app. When I press play on the emulator the message "unable to locate adb" pop-up. How to solve this problem?
I had this problem when updating to Android Studio 4.0.
I even tried uninstalling (and doing a full cleanup) Android Studio and installing again. The problem persisted.
The problem was that when importing my old project, the new Android Studio couldn't find the SDK and my project had no SDK (even though it could build, go figure).
So check File -> Project Structure -> Project. In my case there was a big red NO SDK set there. Once I set the SDK to the one installed, problem was solved.