Virtual machine installation issue.

Ralf Corsepius ralf.corsepius at
Fri May 7 15:27:10 UTC 2010

Preliminary remark: I am not familiar with VirtualBox.

On 05/07/2010 04:11 PM, Kim George wrote:
> I think I solved my first problem but a new problem has manifested itself. On the first issue, I thought the machine was hung, but I noticed under the session information dialogue that the virtual machine was reading data. I let the machine run for about 15 minutes "hung" on the cursor and it finally came up with the following error:
> "This kernel requires the following feature not present on the cpu: pae/nx"
Is this the Fedora guest, which is issuing this message?

Then it's not  unlikely you installed a Fedora kernel which is 
incompatible to your VM. Fedora i386 comes with different 
kernels-variants. The default one is a pae-enabled kernel (package name

> Turns out this is a known error as described here for Ubuntu 8.10 (Still a problem with 9.10 obviously):
> The workaround on VirtualBox version 3.1.6 is to enable pae/nx feature. Right click on the fedora machine you've setup (must be shutdown) follow the path:
> settings>  system>  processor>  enable pae/nx
> The system boots now however after a while it arrives with the following error:
> "prefdm respawning too fast stopped"
> The screen goes blank and the boot process hangs.
Possible, but I am having doubts it accutally hangs (Did you try to log 
into a console (Ctl-Alt-F<N>?).

This message normally means that something went wrong with starting the 
display/desktop manager (typically gdm). The causes for this can be 

> From reading through Fedora forums it appears to be a problem with a failure of the X-configuration as described here:
Yes, a broken/bogus xorg.conf is not unlikely the origin of such issues.

> The workaround appears to be to rename the xorg.conf file?????
Well, I guess you actually mean to remove xorg.conf or to rename it into 
a backup file.

This may well make sense, because Fedora's xorg is equipped with 
automatic GPU detection, which should enable xorg to automatically 
detect its required settings. This works in many standard 
configurations, but occasionally fails badly.

In the latter case you need an xorg.conf and may even manually tune it.

> Does anyone have any ideas how I could go about doing this for a virtual system?
My advice: Try switching to a console (Ctrl-Alt-F<n>) and try checking 
your Fedora's /var/log/boot.log, /var/log/dmesg, /var/log/message and 
/var/log/xorg*.log. These are not unlikely to provide you with further 

Another way to get you further is to try booting into an 
X11-less/console-only runlevel (Normally being done by appending a "3" 
(runlevel 3) to your kernel's command line).


More information about the users mailing list