ymsgr_tray.exe is the main process belonging to the Yahoo Instant Messenger application, an Internet messaging program. The process installs an easy access icon onto your tray bar and is often an autostarting process, which proceeds to initialize Yahoo Messenger. This is a non-essential process.
Disabling or enabling it is down to user preference.
Non-system processes like ymsgr_tray.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues