This occurs because your game client does not match the version on our servers.
Other players and non-player characters display "Unknown" instead of their name.
You can only have one copy of a unique item at a time
What to do if you want to swap the names between two of your characters.
Troubleshooting steps to resolve error message in World of Warcraft.
ゲーム内で World of Warcraft Twitch Drops報酬を受け取れなかった場合の対処方法
Steps on how to reduce the size of your Heroes of the Storm Installation
ディアブロ II リザレクテッドを購入した後、ディアブロ III(2000年)またはディアブロ II Lord of Destruction(2001年)がインストールできない場合