Unable to execute dex: Multiple dex files define Lcom/myapp/R$array;

I had the same problem, quite weird because it was happening only when using Eclipse (but it was OK with Ant). This is how I fixed it:

• Right click on the Project Name
• Select Build Path -> Configure Build Path

• In Java Build Path, go to the tab Order and Export

• Uncheck your .jar library

Only sometimes: In Order and Export tab I did not have any jar library there, so I have unchecked Android Private Libraries item. Now my project is running.

My problem was resolved after cleaning up some directories and files left over from the previous versions of the tools. ADT Rev 14 changes where binaries are stored. I deleted the entire bin directory, restarted Eclipse and cleaned the build and forced a rebuild. That seemed to do the trick initially but the problem came back after the next run.

I finally discovered that my bin directory was included in the project build path. I excluded bin from the build path and repeated the steps above. This resolved my problem.

[Solved for me]

Eclipse project properties->Java build path->Order and export

Uncheck Android private libraries.