[AbRASiON]

Thank you. But what does it mean to set up as an external drive on CCwGTV? can you please write me what steps i should take? so if I have to prepare the USB drive first, then install Kodi, then grant authorization and then run Kodi, then copy the data and finally configure the new path? Thank you.

Kodi can be installed first. The app is going to be on internal storage. "Setting up as an external drive" means I formatted the drives on my PC, and I don't remember doing anything in Android except NOT setting them up as internal storage. What you don't want to do is format as internal storage inside Android. After exiting Kodi, setting up xmbc_env.properties, and moving your existing .kodi folder to the external drive, before starting Kodi the next time, that's when you want to go into Android settings and give it storage permissions. Then when you run Kodi, it should use the data on the external drive.

great, it works. thank you very much!  so now when I update the library, everything will be stored in external storage? The last problem I discovered is that I can't see the external drive when I want to add a new file source for the video library so I cant add a specific folder as a new source. On the contrary, a whole external disk was added as a source, but I am not interested in it. So far, I've solved this by finding the specific folder on the external disk and setting it as a TV Show type to add to the library, but maybe that's exactly the right solution.

Just to clarify what you're talking about here.

I could be wrong, but there's 2 ways to add storage to Android / Chromecast.
In order to copy the thumbnails to the USB drive, you need to make it a 'system' drive - which is what you've done.
In doing so, it becomes difficult to use the USB stick as a media device.

You'll note when you format the USB in the Chromecast you can choose 2 types.
You'd be better off keeping media on the NAS