Error downloading apps in Google Play Store with Samsung Galaxy S3: "Package file invalid" Whenever I try to download an app in the Google Play Store on my Samsung Galaxy S3, it keeps saying "package file invalid" and won't let me download anything. The message also has a triangle with a ! inside it.
Try downloading via WIFI.

I had this issue recently, same phone. Tried a few times; both on PC and on the device itself each failed. I realized WiFi was off (mobile data only). I turned WiFi on and the file downloaded first go.