Around the time that the latest update to Google Play started rolling out, some users have reported receiving an error message when trying to download/update applications. The error reads as “Package File Invalid,” then that’s basically it. Google posted on their Support page that they have received enough reports from users and are currently working on a fix for the issue.
We’ve received reports that some users are getting “Package File Invalid” while trying to download or update apps.
We’re currently investigating a permanent solution, and there are no workarounds at this time.
We’ll continue to update this page with developments, so check back soon.
So, if this problem has been plaguing you, rest assured in knowing that Google has their brightest minds on the problem.
Via: Google Support