Try pressing escape when it is frozen to see the shutdown commands behind the splash screen. Or remove
"quiet splash" from this line in etc/default/grub
you can do this by editing the etc/default/grub file
sudo gedit etc/default/grub - make the edit so it looks like this
If you had other parameters between the "" you can leave them in the line
then update grub with
On start up and shut down you should see the boot sequences commands now.
If you see
Reached target shutdown and that is where it hangs forever this may be related to bug #1464917:
If you feel this is related to this bug please go to the link above and add your name to the "This affects me " link at the top of the bug description
There has been a development as a work around to this bug. It seems to be related to the swap file usage/management. Adam (from the bug link above) points out that if you turn your swap off, wait for it to process, before you shutdown the hang never happens. When you are ready to shutdown your machine, open a terminal window and type;
sudo swapoff -a
Wait for the command to process and give your prompt back then you should be able to perform normal shutdown. This is working for many including me.
After the shutdown or reboot has hanged with this message
Reached target Shutdown
- Hold down the Alt and SysRq (Print Screen) keys.
- While holding those down, type the following keys in order, several
seconds apart: REISUB
- Computer should reboot.
You can also try the following after it hangs.
see if you can login tty1 and reboot
- Write your username (lowercase, the name of the user folder in
/home) and hit Enter
- Write your password (nothing will appear) and hit Enter
If your password and username are correct, you are now logged in.
If that fails try
Ctrl+Alt+Del a couple times at that point in the tty1 screen
You might see a message that states the machine is going to reboot and then it should do just that after a minute or so.
Its better than a hard boot - until its fixed
In the bug notes it is reported that you can upgrade to Vivid-Proposed and it fixes the issue but some still see this after that upgrade. It might be worth a shot.
Btw the same bug affects me.