Is there any way to completely block any app from using data (Android 6.0) I have a problem: my house wifi goes down a lot for some unknown reason, and so I turn on data to continue whatever conversation I was having on my laptop on my phone. Then I forget to turn on wifi when the internet comes back on, and I watch YouTube videos on my phone. This, in turn, eats up 500mb of my 1gb data plan. This has happened three data cycles in a row.

When I select the YouTube app in the data section of my settings, even when I select the "restrict background data" option, and even when I go into YouTube's settings and select "only stream HD video on wifi", it still uses data. It seems like there is absolutely no hope for preventing this app (or any general app for that matter) from using any data at all.

I couldn't even find a good third-party data management app that has this functionality. Every app I've found only allows me to read and analyze my data usage and set 'timers', but no way to completely prevent specific apps from using any data. I decided I would just completely eliminate YouTube, which was annoying in and of itself because it seems there's no way to uninstall a factory-installed app. I ended up just disabling it in my settings, and then blocking it entirely with a third-party app called Boomerang.

Please, is there any simple way to completely block all data usage of only a specific app? Why is this such an unheard-of request?
One simple way to manage what application will use your mobile data is using Triangle by Google. Get it on APKMirror or APKPure and install it with ADB. Plenty of alternatives are offered here.

There are also a great number of ways you can save on mobile data usage. You can use less data with Chrome's Data Saver. You can set mobile data usage warning and limit. For example, set the limit at 1 Gb and the warning at 0.618 Gb. You can use Firefox Focus or Firefox with uBlock Origin. If you are rooted, you can get AdAway on F-Droid.