Installation
How to Enable Unknown Sources / Install Unknown Apps
One global switch became a per-app permission in Android 8. Where to find it on each major Android flavour.
What changed in Android 8
Android 7 and earlier had a single Unknown Sources checkbox that authorised the whole device. Android 8 replaced it with REQUEST_INSTALL_PACKAGES, granted individually to each app that wants to trigger an installation. The practical effect: granting it to your browser does nothing when you open the file from a file manager.
Where the setting lives
| Platform | Path |
|---|---|
| Stock Android 8+ | Settings → Apps → Special app access → Install unknown apps |
| Samsung One UI | Settings → Apps → ⋮ → Special access → Install unknown apps |
| Android TV | Settings → Apps → Security & restrictions → Unknown sources |
| Fire OS | Settings → My Fire TV → Developer options → Apps from Unknown Sources |
| Android 7 and earlier | Settings → Security → Unknown sources (single global toggle) |
Worth knowing: The permission is REQUEST_INSTALL_PACKAGES and it is held by the app opening the file, not by the file being opened.