Clonezilla fails with warning (mismatched GPT and MBR partition)

[Brent_Santin]

Sorry, I did not understand what you were instructing about gdisk at first as this is my first time using that command. In the case where I entered sudo gdisk -l /dev/sda as instructed by you above, it did not provide the COMMAND prompt for me to confirmation either "W" or "Q".
So no, I assume then it did not write.

I did a little reading about gdisk and tried the following (omitting the -l parameter this time):

brent@i5tower:~$ sudo gdisk /dev/sda
GPT fdisk (gdisk) version 1.0.5

Caution: invalid main GPT header, but valid backup; regenerating main header
from backup!

Warning: Invalid CRC on main header data; loaded backup partition table.
Warning! Main and backup partition tables differ! Use the 'c' and 'e' options
on the recovery & transformation menu to examine the two tables.

Warning! Main partition table CRC mismatch! Loaded backup partition table
instead of main partition table!

Warning! One or more CRCs don't match. You should repair the disk!
Main header: ERROR
Backup header: OK
Main partition table: ERROR
Backup partition table: OK

Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: damaged

Found valid MBR and corrupt GPT. Which do you want to use? (Using the
GPT MAY permit recovery of GPT data.)
1 - MBR
2 - GPT
3 - Create blank GPT

Your answer: 1

Command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): n
Aborting write of new partition table.

Command (? for help):

As you can see at the end there I pressed "N" to abort (out of caution). So at this point I'm to press "Y" instead to write, correct? Once I get your confirmation that I understand this correctly I will proceed.

Thank you VERY much!

[oldfred]

Yes, that should work.

[Brent_Santin]

Well, I'm posting from my spare laptop now, because after doing that and rebooting all I get is a black screen with a flashing cursor. So I guess my boot record was corrupted? Anything to do besides reinstalling Lubuntu 20.04 from scratch?

[Brent_Santin]

I'm just going to reinstall.

[oldfred]

As mentioned you may need fsck and reinstall of grub.
But if more than an hour or two trying to repair, then reinstall & restore from backup if quicker.

[tea for one]

As mentioned you may need fsck and reinstall of grub.
But if more than an hour or two trying to repair, then reinstall & restore from backup if quicker.

I agree - after spending an hour or two trying to repair, re-install and restore backup is easier and less stressful.

When you boot into a live session, double check that you have booted in UEFI mode and then create a GPT partition table using gparted or similar partition editor.

Clonezilla will then have little reason to complain .

[Yellow Pasque]

FWIW, you probably should have selected option 2) GPT to restore the main GPT from the backup. You clobbered it using MBR.
I'm more familiar with this menu, where you would have chosen 'b' instead of 'f':
http://rodsbooks.com/gdisk/repairing.html

Sorry, I know hindsight burns..

[oldfred]

If a BIOS boot install on gpt partitioned drive, it would have a bios_grub partition. His screen shot did not show a bios_grub.
Or it would have given grub errors on install to gpt without a bios_grub and would not have been bootable.

I still suggest to use gpt and if UEFI system, use UEFI install to gpt drive. With UEFI you have to have a ESP - efi system partition, FAT32.

For several years when thinking about a new UEFI system, I partitioned with gpt, but put both bios_grub for current system but also an ESP, so I could move drive to new system & just reinstall grub to have it be UEFI bootable.

[Brent_Santin]

Okay, after a late night during which I *nearly* threw in the towel, I've finally got my system up and running.

The whole problem (explained in my original post) was my lack of understanding of UEFI vs. BIOS and GPT vs. MBR. My old computer was from 2006, so still had standard BIOS/MBR. The new one is from ca. 2015, so knows has UEFI and knows how to deal with GPT boot records. I had never dealt with a computer that used EUFI and GPT before.

Not knowing the differences, I chose to boot the Lubuntu Live installation from my DVD drive using the non-UEFI legacy mode (by hitting F12 at power-up and selecting that choice in the BIOS' boot priority menu). Unfortunately, whatever mode you boot the installation disk in is the mode in which Lubuntu installs itself on the hard-drive (this was not obvious during the installation process, but even if it had been I probably wouldn't have caught-on given my state of knowledge at the time). So, by installing Lubuntu the "legacy" way I wrote a new MBR over top of Windows 10's GPT boot record. This caused the GPT/MBR mismatch Clonezilla was complaining about.

My solution (after trying several failed re-installs and buggering up the hard-drive completely by erasing partitions -- especially the UEFI partition -- and not understanding how to set them up again) was to restore the system to the way I had received it ---- with only Windows 10 on it (fortunately I had made a backup image of the hard-drive in this state). In doing so this also restored the EUFI partition I had wiped.

Next, I installed Lubuntu from the live DVD, this time making *SURE* to boot the DVD drive in EUFI mode (my BIOS boot priority selector has two choices for my DVD drive: EUFI and "non EUFI"). Lubuntu installed fine this way over top of Windows 10, and now when it starts it does show the GRUB menu, whereas under the old messed up Lubuntu MBR/GPT mismatch installation it did not!

So once I got the system up with a fresh install of Lubuntu, I wanted to immediately make a backup image of it (and test to see if Clonezilla worked this time). At first I used a DVD of Clonezilla 2.2.x, which when booted in EUFI mode will not start (a screen comes up explaining that it failed to start). When the Clonezilla DVD is booted in legacy "non UEFI" mode it DOES start, but fails to back up the partitions to an image file (it tries, but reports that each partition did not back up properly - maybe because in this mode it does not understand EUFI/GBR?).

So then I made a DVD of Clonezilla version 2.7.x (the latest at the time of me writing this). It WILL boot into EUFI mode without complaint, and DOES back up all partitions properly in this mode. So I guess there have been improvements to Clonezilla since 2.2.x.

Whew! That took a lot of steps and a lot of aggravation. However it's probably worth it though as Lubuntu is properly installed and I now have a basic understanding EUFI and GPT.