Not sure why its done that....
1st to clear cache for all app go to storage and on that page go to cache and then click on it and clear.
Now to the other if you watch a movie it should only stream ahead a little, if it streams to far its set to zero cache and that can cause problems.
Now the only thing you can do is to go setting, other, more setting and this time apps and scroll down to Kodi, then force stop and then clear data.
Go back out and restart your box, now go back to Kodi and try and run the droidbox wizard if it will let you. If it does happy days if not then there's a thread on here about what to do.
If you do manage to get it running again check how far its streaming if its to far let me no and we will sort it.
Also keep an eye on your memory as it soon fills up. Hope this helps and I'm off now till later on so Good Luck