I am trying to modify k-9 mail and I have done basically what I need. The only issue I am faced with is changing the package name. I have tried using refractor built into eclipse, I have also tried using the tool in the ADT plugin to change the package name. I also tried them both on same source, with no luck. What happens is the name of the package changes, it updates all of the references, the project compiles and installs on my phone. After this i can run some of the app but when the program starts new activities the program force closes. Has anyone been able to change the package name? If so how? I can provide the source I am working with and anyone can try on my source. Thanks in advance.