• Windows* 98/NT 4.0/Me/2000/XP (or higher),
• Yahoo! Messenger 6.0, 7.0, 7.5, or 8.0 (any languages).

(*) Probably need to update Windows (see below).

• CLOSE ALL PROGRAMS BELOW BEFORE TO LAUNCH SETUP ;
• Yahoo! Messenger,
• Y!Tunnel (Basic or Pro),
• Y! Pilot and anothers tools of  Y!M Plus,
• Others plugins or tools for Yahoo! Messenger.
• Check into your Windows Taskbar (on bottom-right)
  that any previously programs run,
• Perhaps you will need to restart Windows if some system's files are used,
• If you have some errors while installing or using Y!M Plus, download this Microsoft updates ;
• Visual Basic 6 Runtime,
• MSXML 4.0 core services (Only "msxml.msi" file),
• And others advice's updates from Microsoft Windows Update.
• Otherwise, mail to support for Y!M Plus.

Last minutes advices : readme.txt