If you already have a drive mounted as internal storage, hit build number 7 times or whatever it is to enable the developer mode and then turn on the ability to force apps onto the external drive. That’s the trick I had to find that helped get me past the low storage nag alerts.
Guys, after a few days I am now sure that the problem is caused when I mount my samba server as network storage on Shield's settings.
I unmounted my server from shield and I added it manually to some apps like solid explorer, kodi etc., and my storage is not getting low any more.
If you have any idea what makes my samba server to fill up shield's storage when is mounted as a network storage, please let me know...
Just plug in an external USB3.0 drive and mount it as adoptable storage. The OS will abstract this as internal storage. Done.
Install a file explorer and delete old stuff like videos or download apks pictures etcs, then clean the cache of certain apps and remove apps you don t use make sure you check most folders