Me and my sister were going to play on a world together. This world on is my computer, and she was connecting to it with her computer via LAN. She wanted to play by herself so i just decided that it would be easier if she logged in on my computer and played on the world from there instead of having to set the world to LAN and have her computer connect to it. But when she started playing she had my player's inventory. So we decided to do what we normally do which is have my computer set the world to LAN and have her computer connect to it, but when she joined her inventory was still mine.