When I try to start 'screen' or 'byobu', I get the following error message:

$ screen
No more PTYs.
Sorry, could not find a PTY.
[screen is terminating]

I seem to have enough though:

$ ls /dev/pts  
$ cat /proc/sys/kernel/pty/nr
$ cat /proc/sys/kernel/pty/max

Some more info:

$ uname -a
Linux cube.mydedi.net 2.6.18-194.8.1.el5.028stab070.5 #1 SMP Fri Sep 17 19:10:36 MSD 2010 x86_64 x86_64 x86_64 GNU/Linux

If you need any more info please comment. This is on a low-end VPS, but it used to work just fine, until it stopped working. Everything else seems to be fine though.


Having zero ptys is unusual, as the very SSH connection you are using has a pty allocated.

Make sure you have devpts mounted:

$ grep /dev/pts /proc/mounts
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620 0 0

If it is not:

# mount devpts /dev/pts -t devpts -o mode=620
  • You were right. A simple "sudo mount devpts /dev/pts -t devpts" solved my problem. Not sure why is devpts not auto-mounted though... – Attila O. Jun 27 '11 at 8:56

I had a similar issue, but my problem arised when I started an LXC container within my system (and stopping it didn't help). It turned out that when screen (in my base system) was trying to open a new PTY, it was opening one that was already existing, and couldn't change its ownership.

It was very strange, but the most obvious place was the /dev/pts mountpoint, so I simply remounted it:

# mount -o remount /dev/pts

and the problems went away. I didn't "lose" any PTY devices from /dev/pts after remounting, so it seems a pretty safe operation.


I had similar issue, but the problem was wrong permissions of /dev/pt* devices.

Not sure why they were set to 600, so only the root could use screen, I changed to 666 and it worked for other users.

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