I have Android Studio Beta. I created a new project with compile my old modules but when I tried launching the app it did not launch with the message:
Error:
Enable
defaultConfig { multiDexEnabled true }
If step 1 doesn't work then
Go to project structure and find out the external library which is using a different version. Double click on it and delete its jar file. Close the project and open again android studio will rebuild the project. The problem should be gone.