I can't find files taking up space in my android phone I have bought Lenovo k4 note and have recently upgraded to Marshmallow. So I've 16 GB of internal memory out of which the Android 6.0 inbuilt memory app inside storage and USB setting, says 5.37 GB is OS occupied. 9.46 GB out of 10.63 GB is used. Further break down are as follows:


Apps 5.29 GB 
Images 105 MB
Videos 8 KB
Audio 588 KB
Other 488 MB
Cached Data 183 MB


Which totals to 6.066 GB. 

So now subtracting 6.066 GB from 9.46 GB I get 3.394 GB which I can't understand where it went.
Still after going inside file manager and clicking the view hidden files these are what I get:


Android 2.17 GB 
Download 278.01 MB
Shareit 200 MB
WhatsApp 136 MB
Pictures 74 MB
Books 52 MB
DCIM 29 MB


Which comes to around 3 something GB and still 3 GB are missing.. so.. around 6 GB of files are not showing.. I am unable to find the files that are taking up space. Can anyone help please.
I also had the same problem with my Android.

But after doing some researches i found that the google apps Google docs Google sheets and Google slide are taking much space .

When i looked for the app info of these apps, i found that all of these are taking at least 200mb of space where as i never use them.

So i cleared the data and all problems solved.

But if still the problem does not solve, you should finally factory reset your device.

Hope it helps.