Hello. It is a bug in grub: https://bugzilla.redhat.com/bugzilla/long_list.cgi?buglist=114690 To solve: 1) Boot from first CD of CentOS 'linux rescue'. 2) From shell start 'grub' 3) From grub execute the following: root (hd0,0) setup (hd0) root (hd1,0) setup (hd1) Reboot Miguel R. Fajar Priyanto escribió: > Hi all, > I'm trying to setup a RAID-1 with Centos4.2 on HP Netserver E60. The raid > consists of 2 9,1GB SCSI disks. > > The partitioning and installation process went smoothly, but after it finished > and rebooting, there is an error: Missing operating system. > > The partition is: > / > /home > swap > > Bootloader is on device md0. > > What could be possibly wrong? > Thank you, >