“Conversion to Dalvik format failed with error 1” on external JAR

Question

In my Android application in Eclipse I get the following error.

UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already add

Answer 1

EDIT (new solution):

It looks like the previous solution is only a bypass. I managed to finally fix the problem permanently: In my case there was a mismatch in android-support-v4 files in my project and in the Facebook project that is referenced in my project.

I found this error by performing Lint Check (Android Tools / Run Lint: Check for Common Errors)

My previous solution:

I've tried any possible solution on this site - nothing helped!!!

Finally I've found an answer here: https://groups.google.com/forum/#!topic/actionbarsherlock/drzI7pEvKd4

Easy steps:

Go to Project -> uncheck Build Automatically

Go to Project -> Clean... , clean both the library project and your app project

Export your app as a signed APK while Build Automatically is still disabled