[SOLVED] Loss of power shutdown, Invalid partition table on reboot

[Shady Medic]

Hi there, I think I got into quite a trouble.

So I have dual boot on my laptop, Windows 10 and Linux Mint (one of the newer versions, installed from an ISO downloaded as "latest release" like an month ago).

I was using Mint today, running low on battery, but it didn't seem critical yet. I think I was just browsing through some folders when all of the sudden, the screen went black and all lights did so. I guess the battery status was showing more % than there actually was left and the computer just run out of power.

So I plugged it into electricity, let it charge the whole afternoon and then tried to turn it on again.

First, there was some message about system date being set incorrectly or not at all or something like that. Pretty sure I already saw this message before, didn't think much of it and just pressed F1 to continue.

At this time, OS selection prompt would normally show up, letting me select between booting to Windows or to Mint. But in my today case, the only thing that appeared was "Invalid parition table!" message. I shut the laptop down by holding the power button and then turned it on again, only to get the exact same message after restart (without the "no date set" warning this time).

So... how do I undo this? I have some rather important files saved in my /home folder, that aren't saved anywhere else (they are just a few plain text files, not more than 50 kB in total). If it wasn't for them, I wouldn't mind reinstalling the whole system. But at the same time, I find it hard to believe that unexpected shutdown of the Mint OS could mess up the EFI partition (which is what I suppose is being accessed by the bootloader at the moment when the "Invalid partition table!" message appears.

My disk is (or was?) partitioned in the following way:
/dev/sda1 EFI
/dev/sda2 Windows "root"
/dev/sda3 Windows recovery partition
/dev/sda4 Windows Users (the Users folder)
/dev/sda5 Linux /home/
/dev/sda6 Linux root

TL:DR: Read the bold text only for quick idea what's going on

[BG405]

If you boot from a live USB (e.g. the one you used to install Mint) you could try running a disk check from there. Hopefully this will fix things? (I assume you were in the Mint OS when this happened). You might also be able to retrieve the files you need, if it doesn't make it bootable again. Sorry I'm not too familiar with Win10/11/etc. dual-boot.

[MiZoG]

First, get into UEFI/firmware setup and check/correct system time.
Then, while being there double-check your boot device priorities.
If none of it works, you got to try to repair filesystems but this is done differently on / for Windows from Linux.
At least boot into a live session with an installation media (let's say a USB stick with latest Mint) as BG405 already suggested and try to fix Linux partitions.

[Shady Medic]

Thank you both for your replies. Can you please go more into depth about how do I repair the partitions from live session?

[BG405]

Since you have Windows partitions I wouldn't recommend running fsck to attempt to repair the filesystems just yet, apart from fsck -N to show what would be done, without it altering anything, for now.

I assume Windows is also not bootable.

But, from the Live session, it's worth reporting the output of e.g. sudo parted -l, lsblk and maybe blkid just to see what those come up with.

Or, again also from the Live session, see what GParted shows for your hard drive.

[MiZoG]

Easiest I believe way to check / repair your disks on a live session:

1. Open "Disks
2. Select your Linux partition(s).
3. Press the cogwheel icon --> Check Filesystem and/or Repair Filesystem

I believe Disks can handle the EFI/ESP vfat partition as well (running dosfsck in the background).

[AndyMH]

But in my today case, the only thing that appeared was "Invalid parition table!" message

I believe testdisk will fix this for you and I think you will find a copy on your mint install stick.

Assuming you are booting UEFI with a GPT partition table, there is a backup copy of the partition table at the end of the drive. This may still be intact. gdisk can repair from the backup table.

As a first step, boot your install stick, open a terminal and run testdisk, post what it outputs. This is a how to on testdisk:
https://www.cgsecurity.org/wiki/TestDisk_Step_By_Step

[Shady Medic]

Thank you all for your replies, seems like the damage was rather limited, because I was able to fix this just by editing BIOS setup.

When I pressed F12 during boot and got into selection between legacy boot (some options I don't remember) and UEFI boot (with options "ubuntu", "Windows Boot Manager" and "Onboard NIC"), I could select "ubuntu", which took me into the OS selection that was loading by default before the crash. From there, I could boot into Mint or Windows just fine.

So in BIOS setup, I switched to UEFI and disabled Windows Boot Manager and Onboard NIC, leaving only the checkbox next to "ubuntu" checked.

I'm not sure what happened and I'm not very sure whether I was using legacy boot before, but at least it works now.

[AndyMH]

First, there was some message about system date being set incorrectly or not at all or something like that. Pretty sure I already saw this message

I'm guessing your BIOS reset itself to legacy boot, which would explain (partially) the message about an invalid partition table. It was looking for a legacy partition table and not finding one on a GPT partition table drive.

Suggest you replace your CMOS battery.

[BG405]

Just posting to add a note that in my experience, and possibly for future reference, legacy (BIOS, CSM) boot works fine with GPT.

I guess it was just the boot options as per the OP's findings? I use GPT exclusively, regardless of legacy or (U)EFI boot. This (Manjaro) and my Mint machine both run in Legacy mode on GPT. Perhaps it's the lack of the bios_grub in the OP's case causing that "false alarm"?

I also guess (U)EFI boot won't work with MBR partition tables.

.. but, yes, time and date being lost does indeed point to a dead CMOS cell (usually a CR2032).