McAfee Free Antivirus won't update from Play Store returning error -505
The app with this package name: com.wsandroid.suite was not signed by the same certificate as the one from the Play store.  This is a fundamental security requirement.  You will have to make sure the app you are installing originally is signed with the same key as the one in the Play store.

There is no way to get around this security requirement (matching signatures) to the best of my knowledge.