Hi,
its very easy I had the same problem transferring files and downloading apps.
Just go into settings>storage check and swipe across to details and go down to clear temporary files. Somehow all files and apps downloaded are stored hear as well (Microsoft need to change this, bit of a pain)
Hopefully that will do the trick (I know it's a bit tedious if you are repeatedly downloaded lots of files and apps)
Hope that helps!
:smile: