Android system takes too much data usage Checking through Glasswire application, Android system has the highest data usage everyday on my Android. I only used my phone for tethering to my laptop and it don't take that much of data (My laptop only has Glasswire apps so I can check).

I have searched through the internet and most of them said you should restrict background data. However, if I set it, I won't receive notification from my instant messaging app.

Also, it seems weird that the upload data usage take more than 100 MB. I realize I even didn't upload too much things.

Are there any solution?
Android System data usage

When you use tether your Smartphone and your PC the I assume that those data will be accumulated in the "Android System" entry - or did you encounter a separate entry in the Android network usage list?

On your PC you should check if the tethered network connection is marked as cellular / metered connection network connection (Windows). 

Background data user

You can restrict the background data usage for ever app separately. Therefore you can spare the apps where you want/need background data.