Why do I get "init: failed to create pty..." errors on boot?

Solution 1:

This is currently a known bug in upstart (Ubuntu's startup manager or init-replacement).

It should not be happening to normal users running the regular Ubuntu kernel on a desktop/laptop, but apparently it does for some of them.

The fix is to add a --no-log boot option to your kernel command line. You can do this by editing /etc/default/grub:

• Alt+F2, then gksudo gedit /etc/default/grub
• Look for the line starting with GRUB_CMDLINE_LINUX_DEFAULT=

• The line normally says this:

  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

• Add --no-log to that line, i.e.:

  GRUB_CMDLINE_LINUX_DEFAULT="quiet splash --no-log"

• Save and exit. Reboot and the errors/warnings should be gone.

Technical Explanation

According to comments in the bug report, upstart expects /dev/pts to be mounted and the /dev/ptmx device to exist when it starts, and prints these errors when it can't find the devices. These are set up by the initramfs on Ubuntu, so in theory these errors should only occur on embedded devices, etc. that have no initramfs. They should not be fatal because eventually in the startup process, mountall will ensure that /dev/pts and /dev/ptmx are set up correctly.