FC4 boot shows "no such user : root".
Since it cannot find the user root(superuser) all sorts of permissions are denied as the boot proceeds, leaving a console login prompt which ignores keyboard input. The full line is:

Starting udev : MAKEDEV : no such user : root

There, of course, was a root user in my previous installation of FC2 on this machine. In this installation it asked for a password for root.

Since upgrading to FC4 seems to have wiped out the ability to boot under my old kernels, I cannot boot the machine to make any repairs in a shell.

Please help! Thanks.

Try using a knoppix CD to boot. Then mount your root partition, mount /dev/hda2 /mnt/hda2 and chroot /mnt/hda2 (be sure to use whatever proper dev and partition for your root filesystem). This should give you a root shell on your former system. Try to passwd root or something like that and see if you can reset your root password. If there's still no root user, I'm not sure what to do. But at least you could recover your old files and reinstall as a last resort...

Here's a link to system recovery with knoppix

I obtained and used Knoppix (great stuff), and found that I, indeed, have a root user on my system. I chrooted to my hard disk, and was able to change the password of root.

There is no change when trying to boot. It denies permissions and denies that a user called root exists. Is it even possible to not have a root user in Linux? Why is the loader trying to verify that he exists? Wouldn't all operations at boot automatically be assumed to be done by root?

It would be nice to know which files are controlling the boot at this point and where they are trying to pick up the root user from. The ...no such user : root... happens directly after the "Welcome to Fedora press "I" for Interactive" message. A number of lines appear before this, denying access to various files. How could I possibly be booting as an underpriviledged user? Who would I be?

BTW, Thanks much for the Knoppix info!

I've honestly never seen this error before and google doesn't seem to be very helpful. My only recommendation is to enable your bootlog (on Debian edit /etc/default/bootlogd) and the try to reboot. It should create a file /var/log/boot.log. When the boot fails, reboot into Knoppix and see if there's anything useful in there...

Sorry I couldn't be more help...

I thought of one other thing you might check is that the root account on fedora has a UID and GID of 0 (i.e do the chroot thing you did above). Just look at /etc/passwd file. It should look like

I'm having the exact same problem, none of the above suggestions worked. Any idea why it would simply lose all the user information? Or how to fix this without restoring/reinstalling?
I can use a rescuedisk and see everything on the drive perfectly.

I'm also having this exact same problem on my fathers box. It manifested after some hardware problem (memory), which caused random segmentation faults during boots - after replacing the memory, I now have this problem.

I can boot in single user mode, but when I do a whoami, it says cannot find user with id 0.

passwd, group, shadow etc. files are visible and readable, and user root, gdm and others are there.

/ is mounted on '/dev/VolGroup00/LogVol00', which seems a bit strange....

I'd really like to repair this - everything is there, the system has just somehow lost where to look for users...

https://bugzilla.redhat.com/show_bug.cgi?id=192072 Check this bug