Can't upload Android app to device (stale dexed jars)

I have also encountered this problem in Android Studio, from version 2.0 Preview 6 all the way up to 2.0 Beta 3 and none of the solutions mentioned here worked for me.

Turned up it had nothing to do with Instant Run. All I had to do was to increase the AVD's Internal Storage until the following notification disappeared. I also had to perform a data wipe after changing the values.

I disabled Instant run for this project, and problem solved.

Maybe it's a bug in the instant run feature of Android studio 2.0 preview.

Instant Run is a new feature introduced in Android Studio 2.0.

ps: in case you don't find Instant run, its in:

Android Studio --> Preferences --> Build, execution, deploy --> Instant run.

or you can search for it in the preferences tab.