After the update of lol5 on May 5th, a large number of customized skins could not be used manually. Documents mounted in Raven rabbit skin that can be used should be deducted from the official.
CC league of legends homemade skin managers have it. If the automatic mount is not successful, it is very simple. Just put it in the folder after loading. See the folder you mounted, copy the decompression package you downloaded, and then rename and replace the decompression package you mounted. That's how I got it.