Make sure that MSN is enabled ingame.
Run SC and osu! on same permission level (both as normal user, or both as administrator)
Make sure that your antivirus isn't doing something weird(especially sandboxing) - try adding exception in it.
Run SC and osu! on same permission level (both as normal user, or both as administrator)
Make sure that your antivirus isn't doing something weird(especially sandboxing) - try adding exception in it.