He restarted his laptop because it was lagging. When he came back, all his beatmaps and his handmade skin were missing. We tried searching for them in the osu folder but they were missing. He was using the latest version of osu. If anybody got an idea how to help I would be extremely grateful! 
Video or screenshot showing the problem:
osu! version: 20171227.2 (latest)
Video or screenshot showing the problem:
osu! version: 20171227.2 (latest)