How to: Adb install apk get error, INSTALL_FAILED_ALREADY_EXISTS

If you are a developer, and want test your new build and keeping the old settings of your app.here is the quick answer.

TRY install the new apk, you will get [INSTALL_FAILED_ALREADY_EXISTS] failure.



here is the trick, add the –r, will keep the old setting while applying the new app.