Cause: Accessibility service disabled.
Fix: Settings → Accessibility → Nova Launcher → ON.
Cause: The free version is too new for the old unlocker.
Fix: Ensure both Free and Prime are from the same major version (e.g., 6.x Free + 6.x Prime). nova launcher prime apk android 601
On Android 6.0.1, Nova was the ultimate tool for "themers." Cause: Accessibility service disabled
On Android Marshmallow, Nova Launcher was notoriously fast. Nova Launcher was notoriously fast.