Fedora 17下用yum把Samba升级到3.6.6-91后，发现wndows不能访问。发现samba启动失败，log显示：
systemctl status smb.service
smb.service - Samba SMB Daemon
Loaded: loaded (/usr/lib/systemd/system/smb.service; enabled)
Active: failed (Result: exit-code) since Wed, 11 Jul 2012 07:40:11 +0800; 6s ago
Process: 2073 ExecStart=/usr/sbin/smbd $SMBDOPTIONS (code=exited, status=0/SUCCESS)
Main PID: 2074 (code=exited, status=255)
CGroup: name=systemd:/system/smb.service
sudo tail /var/log/samba/log.smbd
ERROR: failed to setup guest info.
[2012/07/11 07:40:11, 0] smbd/server.c:1053(main)
smbd version 3.6.6-91.fc17 started.
Copyright Andrew Tridgell and the Samba Team 1992-2011
[2012/07/11 07:40:11.812062, 0] smbd/server.c:1109(main)
standard input is not a socket, assuming -D option
[2012/07/11 07:40:11.821222, 0] auth/auth_util.c:707(get_guest_info3)
SamInfo3_for_guest: Unable to locate guest account [guest]!
[2012/07/11 07:40:11.821348, 0] smbd/server.c:1235(main)
ERROR: failed to setup guest info.
原因是，smb.conf中缺省的guest用户在系统中不存在，旧版samba会忽略，而新版的就会报错退出。
解决办法，把smb.conf中的guest用户关闭。
; guest ok = no
; guest account = guest
