Opening an .apk on Android shows a file list instead of installing For a client I build a private app which their employees can download on their tablet and use. To get the app, the employee opens Chrome on his tablet and navigates to an URL to start the .apk download.

This approach worked fine for the last few years, till a few weeks ago. Instead of installing the app, a folder is shown with the files of the .apk.

The only difference I noticed is the source that's stated in the 'Downloads' screen. On June 16th everything worked fine, the source says 'chrome-native://newtab'. As of July 1th, the source changed to the domain where the .apk was downloaded and this problem occurs:



The tablets are only used for this particular app. The company buys a tablet, navigates to the URL, downloads the .apk and installs it. It would like to keep it as simple as this.

I've searched everywhere, but still have no clue what causes this problem. Any ideas?

This problem occurs on Android 8.1.0, the upgrade form 8.0.0 to 8.1.0 may be the cause of the problem. But I still have no idea how to solve it.
The issue happens with an incorrect HTTP header.
If the request has the right Content-Type header: application/vnd.android.package-archive, the APK will be installed correctly.