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I know this has been asked multiple times before, but most of these threads don't have an answer. I tried user62664's solution here and ran sudo update-grub successfully, but nothing changed. This happens whether I type sudo reboot or sudo shutdown -h now. Here is what it looks like when it hangs. There are no error messages, everything shows up with '[OK]', and then:

* Deconfiguring network interfaces...          [OK]
* Deactivating swap...                         [OK]
* Unmounting local filesystems...              [OK]
* Will now restart
[ 1306.738916] mei_me 0000:00:16.0: stop
[ 1306.739745] reboot: Restarting system

This seems like a very common problem, yet there are very few answers and they don't seem to help in my case. Does this mean there is no one solution? In which case, where should I check to check to find out the root cause?

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Try options -H, -P with the shutdown command. Preserve symbols' register. –  Danatela Mar 11 '14 at 3:23
It worked! If there is a similar solution for restart, I would be glad to pick your answer. –  biohazard Mar 11 '14 at 3:53
You mean, reboot? It is only for rebooting computer AFAIK. And it should. I cannot find any reason to shut down computer with reboot command. –  Danatela Mar 11 '14 at 3:56
Sorry, yes, I meant reboot. What I meant in the OP was that the system hangs in both cases, whether I use reboot or shutdown. –  biohazard Mar 11 '14 at 4:04
Try shutdown -r or init 6. –  Danatela Mar 11 '14 at 4:06

3 Answers 3

up vote 2 down vote accepted

From the man shutdown:

       -r     Requests  that  the system be rebooted after it has been brought

       -h     Requests that the system be either halted or powered  off  after
              it has been brought down, with the choice as to which left up to
              the system.

       -H     Requests that the system be halted after  it  has  been  brought

       -P     Requests  that  the  system  be  powered  off  after it has been
              brought down.

As you can see, options -H and -P will poweroff your system. And sudo reboot will only reboot your computer, because it is so designed.

For rebooting your system wishout hanging up I can recommend sudo shutdown -r and sudo init 6. 【⬅This did not work out for me @biohazard】

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Yes, my problem is that the reboot doesn't actually reboot, it stays frozen as described above. Thank you for solving my problem with shutdown, though. :) –  biohazard Mar 11 '14 at 4:01
Update: answer was edited to include sudo shutdown -r and sudo init 6. sudo shutdown -r hangs; –  biohazard Mar 11 '14 at 4:55
and unfortunately, sudo init 6 hangs too... –  biohazard Mar 11 '14 at 5:00
May be the problem is inside your BIOS. Try to update it… –  Danatela Mar 11 '14 at 5:03
Thanks. Well, at least I am able to shutdown using -HP now, so it's already better than before :) –  biohazard Mar 11 '14 at 5:05

Passing a reboot= parameter to the kernel can solve this issue, no matter which shutdown command is used.

See for more details.

In my case, reboot=pci fixed the problem for a Dell Optiplex 790.

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When you make shutdown press super+F1 you will see the problem if it is like the following :

Buffer I/O error on device fd0 logical Block 0

you must then go to BIOS and stop the floppy drive !

if it is something else just say at add comment

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