Wrong UUID at boot
 

I am running LDME with 2 disks.
The disks are partitioned like:
sda1 swap
sda2 /home
sdb1 system (/)

It has been working OK but recently I had to change disk sdb and install a new system.
When I installed MATE/Cinnamon[64-bit] on sdb and rebooted ... GRUB complained ... no such device: UUID xxx-xxx where xxx-xxx is the UUID for the old sdb that I replaced.
I installed GRUB on sdb1.
How do get rid of this error ?

You haven't given enough useful information for anyone to help. The best place to start would be to go to the site below and download and run the bootinfoscript from a Linux install or Live CD. Post the results.txt file here as it will show detailed drive/partition, OS and boot file information.

http://sourceforge.net/projects/bootinfoscript/

UUIDs are unique numbers created when a file system is formatted. When you installed a new system the UUID on sdb1 is now different then what it was for the old drive assume that it was formatted.

What file system are you using for the new sdb1?

It is probably easier for you to boot a live CD and assuming a ext3/4 run the tune2fs command to change the new to the old. You can also run the blkid command to see the new UUID and change grub accordingly.

When giving following commands I was able to install grub (I installed it on both /dev/sda and /dev/sdb to be sure) and after that the system booted OK.

cd /
mount -t ext4 /dev/sdb1 /mnt
mount -t proc proc /mnt/proc
mount -t sysfs sys /mnt/sys
mount -o bind /dev /mnt/dev
chroot /mnt /bin/bash
dpkg-reconfigure grub-pc