It seems that some users are seeing an error when trying to install or update applications from Google Play on their Androids. Instead of the expected behavior — tap a button and install or update an app — users are able to download the package but during install are fed a "Package File Invalid" error.
There are many user fixes floating around out there, ranging from clearing app data for Google Play to removing the proxy address from your APN (this worked for me) but none seem to be a universal fix.
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.
Google has addressed the fact that this is an issue for some users, and is working on a fix. We imagine this has a bit of priority, so hopefully there is good news soon.