I use my MSN in fedora,but I can't find my groups.It is no problem in windows but in fedora, why?
Strange... I've been trying to figure out what causes this. I do not have this problem. I have my MSN contacts in groups in Pidgin, and they sync with other clients like Empathy and aMSN, so obviously they also sync with the MS Live environment. I haven't been using the official Messenger client for 10 years though, and I'm also using Ubuntu instead of Fedora, so there are some differences.
Which version of Pidgin are you using?
Have you updated Pidgin or have you been using the same Pidgin configuration between multiple installations?
You might wanna try backing up and deleting the .purple directory in your home directory to start with a fresh configuration.