Published Android apk gives error “Package file was not signed correctly”

Question

I recently uploaded my application to the android market however it\'s refusing to run when downloaded due to the error

Package file was not signed co

Answer 1

OK I had this same issue and none of the suggested resolutions worked for me. I was signing my app the same way I have been for 2 years and the Android Market was accepting it fine, just users could not download it from the Market with the "Package Not Signed" error.

What it turned out to be was for another project I am working on I had JDK7 installed. It became the default JDK and for some reason the keytool for JDK7 is signing the package in a way that Android must not like. So I reverted to JDK 1.6.0_23 and re-ran my build and put it on the Market and everything went back to normal.

I hope this helps someone else.