Ubuntu – Start-up error: ALERT! /dev/disk/by-uuid/xxxxxxxxx does not exist. Dropping to a shell!

bootgrub2

I have a serious problem with Ubuntu 14.04. When I start my computer it shows the following errors:

Gave up waiting for root device. Common problems:
  — Boot args (cat /proc/cmdline)
    — Check rootdelay= (did the system wait long enough?)
    — Check root= (did the system wait for the right device?)
  — Missing modules (cat /proc/modules; ls /dev)
ALERT! /dev/disk/by-uuid/xxxxxxxxx does not exist.   
Dropping to a shell! 

BusyBox v.1.13.3 (Ubuntu 1:1.13.3-1ubuntu11) built-in shell (ash)   
Enter 'help' for list of built-in commands.  

(initramfs)

I got this error earlier but it fixed automatically, but this it keeps saying this errors. Please please help me.

Update from Comments below

sudo blkid
/dev/sda1 :Label="backu" uuid="c4406f0a406fo312" Type = "ntfs" 
/dev/sda3 : Label="linux"c6e7b2c6-5e8f-4a2d-b666-9489ef7c7c8f" Type = "ext4" 
/dev/sda5: uuid="6e0361c9-bbb6-4395-a75e-ef8d645245d0" Type = "ext4" 
/dev/sda6: uuid="740f28da-723a-40d3-995b-3d5dc0d30120" Type = "ext4" 
/dev/sda7: uuid="30c1ba3b-dd3e-4ec2-989b-2e3a3d0d30d8067" Type = "ext4" 
/dev/sda8: uuid="06145b6-0538-4a4b-b424-a5f7a732e8e1" Type = "swap"

Best Answer

I can't comment (due to my reputation), so it looks like I have to write an answer...
I had this problem a few days ago, but it was because I restored an image (clonezilla) on a new partition, and, each time you create the partition (I don't know ,maybe also when you format it), it gets a new UUID, a different one from the one stored in the image content. In any case: look for that UUID (the one you put with xxxx) in /boot/grub/grub.cfg and /boot/grub/i386-pc/load.cfg and correct it properly... BUT, in case you recreate the partition (that was my case), DO NOT change the UUID on those files, it's better to change the new UUID of the partition for the previous one it had with:
tune2fs /dev/{device} -U {uuid}

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