OS disk in backup uses MBR disk. This may cause boot issues on UEFI systems

[daystrom]

Support case 05703721
I get this message when I try to restore:
OS disk in backup uses MBR disk. This may cause boot issues on UEFI systems.
I've seen https://www.veeam.com/kb3156 that talks about switching the bios to use legacy mode. Before I try that I need to understand things a bit better.
I believe this bios does support legacy mode. If I switch to that, let's say the restore goes ahead without issue.
[1] I restored this same backup to another pc that has UEFI bios, and didn't see this message. Why?
[2] If I restore with the bios in legacy mode, can I then switch back to UEFI in the bios? I'd have to imaging UEFI is the way forward.
[3] The pc that was originally backed up does not have the bios set to legacy mode. But isn't it saying that it was in legacy mode when it was backed up?

[HannesK]

Hello,

Before I try that

I suggest the other way around: try it out and see how it goes. BIOS to UEFI is a bit complex operation https://www.maketecheasier.com/convert- ... windows10/

1) because BIOS to BIOS is fine
2) see my link above.
3) BIOS is legacy. There is no setting to make BIOS "legacy legacy".

Best regards,
Hannes

[daystrom]

I have been calling what is reached by hitting Del or F2 at boot time as "bios". I think you're saying the term "bios" only applies to "legacy bios", and UEFI isn't really called bios?
The original pc that failed already is UEFI.
The second pc that I tried to restore to is also UEFI. But only this onge gave the MBR warning.

Does "OS disk in backup uses MBR disk" mean, the target disk, the disk that I would restore to? Or does it mean the disk that was originally backed up was MBR?

The first post I made here recently was about the apparent failure of the original restore.
post467770.html#p467770
There the restore seemed to be successful, but the UEFI bios (that's what I've been calling it) doesn't show the sata ssd that it restored c to so it can't boot. It does show the 4tb storage drive. It also fails to show another 1 tb sata ssd that has another working os on it. I can't understand that scenario.

[MiGabri]

I can replay to you with some general information about MBR/GPT disk schemes and legacy/UEFI bios info:

- pure UEFI system, so without support to legacy mode, usually can only boot sytem from disk with GPT scheme;
- legacy BIOS system can only boot system form disk with MRB scheme;
- the only hybrid situation are UEFI system with Compatibility Mode Support or Legacy mode that could boot GPT disk in pure UEFI mode or MBR disk in compatibility Mode or Legacy mode

if your OS backup was in an MBR scheme disk and the computer was UEFI that should means that in the source pc the UEFI bios was working in legacy mode or with CSM;

about the restore to the destination pc may be that you received the warning only in a UEFI pure system where you can not boot an MBR disk, and you did not recevive warning in the other system becase was UEFI with CSM support or UEFI working in legacy mode (to verify);

some UEFI bios have some settings to work or not in legacy mode that had to be enabled;

hope to be helpfull for your case

Michele Gabriele
Italy

[daystrom]

Thanks Michele that's super helpful. I don't fully understand yet but it's an area I need to understand better.
After you wrote I checked the ssd that was the boot drive in the pc that had the power event and which I restored to using veeam agent. It is an MBR drive. The pc is using UEFI. I had thought it had the ability to use legacy bios mode, but I think it does not.

This pc use this boot drive ssd for several years. It is MBR, and apparently that worked with the UEFI bios, at least until I needed to restore from veeam.

Is an MBR drive not supposed to work with an UEFI board? It did for several years, but from your write up above (thanks again) it appears that is not expected?

What's the way forward then? Can I format the target ssd as gpt, and then restore from veeam again?

At restore time, does veeam format the target disk with either gpt or mbr, according to the whichever of mbr or gpt are used in the source backup image?

[MiGabri]

As you wrote an MBR OS disk working properly with a UEFI bios without support for legacy mode or CMS is a non expected scenario for me: it would be interesting also for me to underestand clearly in witch way it worked for you, maybe there is something more me too i have to understand;

about your question on converting the backup image, i can tell you for shure that with Acronis True Image that i use in commercial version at office for work i was able in the past to recover an MBR image working on a UEFI with legacy support in a different GPT format on the same pc so that i could change UEFI to work in pure mode without legacy support (also cause on GPT disk windows 10 works better than on MBR); in that case was the software Acronis that in the recover did the change; i did not remember if i had to specify in the recovering process or it did itself; so in some way it should be possible;

about Veeam i am a newbie: i started using the Veeam Agent for Windows few days ago on my private notebook at home, where i was used to backup my pc with the integrate win10 backup (win7 like style) cause windows backup are without compression and so they occupy a lot of space on my backup disks; i tested Veeam in a Virtual Machine and i noticed that the backup are compressed in a better way so i decided to change but i am not experienced with it.

Michele Gabriele
Italy

[daystrom]

Well what I will do is to format the original, target disk as gpt, and then try the veeam restore to it. I don't think there is any risk with this and maybe it will solve the issue. I do hope someone from veeam would answer some of our questions when they get time.

[daystrom]

Unbelivable. I formatted the origanal drive as gpt (it was mbr) and did the restore. Restore completed no errors, though it did warn again with the same msg about MBR disks and UEFI bios.
And it will not boot from the restored drive. The restored ssd is not visible in the UEFI bios.
I have no idea what to try next.
Please someone help out? I'm nearly a week into this issue, the whole experience has been incredibly wasteful of my time and makes me wonder about this restore process.

[MiGabri]

Also if you formatted the drive with GPT scheme maybe that the restore procedure rebuild the scheme in MBR as the backup, did you check if after the restore the drive is still in GPT or not?

[daystrom]

Yes I forgot to mention - veeam restored as MBR.
It doesn't seem possible to convert MBR to GPT and keep the data, otherwise I'd see if I can restore to a legacy bios pc and then convert to GPT, back that up and restore to UEFI.
I may have a backup from veeam that I cannot restore to the original pc. I've had a lot of success with this operation in the past; I hope there is a way forward here.

[MiGabri]

I would try an other way: after recovering the backup image with Veeam you could try use the winPE version of Easeus Partition Master or Aomei Partition Assistant, those software can convert MBR disk scheme to GPT without loosing data;

make a bootable usb with one of those software, boot from it in the pc where you recovered the image and try to convert che MBR scheme to GPT, in the end check if you can boot after that operation;

let me know if you try, i am courious ^^

[daystrom]

That's good news. I'll try that first and let you know.
The other route I can take it to reinstall windows 2012 r2 as the host os from scratch to a gpt drive, and then restore the two virtual machine images. The vms are what count on this pc.
Thanks for your input!

[daystrom]

I converted the drive to GPT. It's still not available to UEFI at boot time.

[daystrom]

A bit of speculation on my part, with little input from the people at veeam who obviously know this stuff inside and out. MGabri here in this thread did pitch in with useful info, and thanks for that.
My guess is that the orignal pc was configured in an atypical configuration, with an MBR boot disk, and an UEFI bios. It appears that's not a supported scenario, or even a scenario that is supposed to work at all. However it did work here for a good number of years. Somehow, either the power event, or the restore from Veeam that followed, changed the formula in some manner, and the restored MBR boot disk could not be presented in the bios. Veeam stores the partition format in the backup, so all of my backups would restore as MBR. Even after converting a restored MBR disk to GPT, it would not appear in the list of bootable partitions in UEFI. I'd guess that was fixable but after a week of almost no input from anyone and so many attempts at x y z, and no easy fix I could find, I gave up on that.
As a result I'm installing the host from scratch.

[MiGabri]

If in the backup there was a complicated server configuration hard to rebuild, may be you could tried to restore the image in a Virtual Machine, also under a pure UEFI system you can run an MBR style disk under a Virtual Machine, after that you could backup again with some other free software that has the possibility to recover and changing the disk configuration meanwhile;
i tried make some google search and Hasleo Backup Suite free, Aomei backupper free and Macrium Reflect should have this feature to be able to recover an image from a Legacy bios system to a Uefi bios system; but that thing let me think that also Veeam Backup should have in someway this feature, unfortunatly i'm still not experienced on Veeam but i would elaborate on this aspect.

[MiGabri]

According to this article: https://www.veeam.com/kb3156 i suppose that Veeam Agent for windows has not the ability to recover MBR image changing to GPT for a pure UEFI system pc; may be that is a feature only awailable in not free Veeam software.

[MiGabri]

An other thing i would to clarify about the scenario of MBR disk in UEFI system is that UEFI system can read/write disk in MBR partition scheme, only can not boot OS from those disks; this means that an MBR disk could normally be used as secondary data disk for esample, and also external usb disk or pendrive in MBR scheme are correctly readed or wrote by a UEFI system;
the thing that you neither saw the MBR disk from UEFI bios is an other unusually scenario for me; you should see as disk, only it should have been impossible boot OS from that disk.

[daystrom]

Yeah, thanks to you and the reading I undertook once you educated me, I realize now that an UEFI board should not have been able to boot from the MBR drive. FYI the MBR drive was not visible to UEFI at all. I can't explain that either.
I've had to move on now so I won't be able to experiment with possible successful restore scenarios. I've done a full reinstallation of the host os.
Thanks for your help on this. I should have had a grasp of MBR vs GPT and BIOS vs UEFI long before now but I never took the time.

[ITP-Stan]

Make sure when you reinstall, that you boot from installation media in UEFI mode.
So that from now on the OS is installed as a GPT disk and boots in UEFI mode.
Easy way to check the UEFI boot mode is that you have a small (<1GB) EFI system partition in the beginning of the OS disk.

New PC's from HP and Dell have stopped allowing legacy boot from internal SSD/disk for a couple of years now.

[daystrom]

Hi ITP-Stan
If you mean, while in UEFI, to choose the UEFI boot option for the usb stick...I don't think I understood about UEFI boot issue at that time. Later MiGabri caught me up a bit. It's likely then that for the veeam agent restore I booted from what is listed as
USB: General UDisk 5.00
and you're saying I should have booted from
UEFI: General UDisk 5.00
and it would have formatted the restore as GPT.

Could you confirm that this is what you mean?

If that's so, it's good news. It's too late now, unless I decide to try it out, since the recreated host is at an early stage and it might be worth my time to experience this working correctly. I sure wasted a ton of time on this, but have learned some new things that I should have known long ago.

[daystrom]

I started a new restore, making sure to choose the UEFI boot from the recovery media, and got the original msg:
OS disk in backup uses MBR disk. This may cause boot issues on UEFI systems
I guess my theory is wrong. The MBR OS disk must be what is in the backup. Booting to UEFI recovery media doesn't seem to have changed how this would play out. It seems to imply that the pc was booting from MBR with UEFI and I thought that was not possible (or maybe just unsupported?)

[MiGabri]

You shouldn't have been able to boot a recovery media from a support with MBR scheme, if your system is pure UEFI it can boot only from a disk with GPT scheme, this also applies to the recovery media you boot from usb.
Are you sure that in the UEFI bios there is not some flag or option where you could enable the legacy support (CSM called sometimes)? Try to explore all the option, maybe that this feature is named someway and it is not intuitive to understand.
For sure make a recovery media in GPT scheme do not change the restore of che image you backed up, the MBR scheme is in the backup cause it was present in the original disk (i suppose); so the recovery rebuild the target disk in the same scheme of the backup.

[daystrom]

I've been through the manual several times include just now to be sure. There is no mention of a switchable bios, between BIOS and UEFI. The line item from the specs is
BIOS Feature - 64Mb AMI UEFI Legal BIOS with GUI support
And in the "bios" I have not seen anything that is recognizable as offering such a feature.
I know, having been able to boot from an MBR disk seems inconsistent with everything I've read since you brought it up. But it did.
This AM I found this:
https://www.veeam.com/kb3156
It seems to offer a way to convert a backup stored as MBR to GPT, with series of commands executed in the middle of the restore process. I will post with success/fail when I know. I'm not sure why I didn't find this article until this AM.

[daystrom]

That method worked, the restore has booted to windows 2012 r2.
The only real hitch was that the hyper-v setup would not run. I found this command that fixed that issue, after a reboot:
bcdedit /set {current} hypervisorlaunchtype auto

[MiGabri]

Glad to read that the procedure described on https://www.veeam.com/kb3156 worked for you, but i am a bit dissapointed from the fact that Veeam Agent for Windows does not manage this scenario in a simpler way.
I also have some other problem in make Veeam working properly with my antivirus on my pc so i decided to try Macrium Reflect for my personal backup at home ^^

[daystrom]

Well, I really appreciate that you helped out with my own issue with agent. Good luck with Macrium.

[ITP-Stan]

Hi ITP-Stan
If you mean, while in UEFI, to choose the UEFI boot option for the usb stick...I don't think I understood about UEFI boot issue at that time. ....

FWIW

I meant when re-installing Windows from scratch make sure you boot the Windows installer USB stick in UEFI mode.
So that Windows will also format the OS disk as GPT and install UEFI bootloader on it.

I'm glad you found a way to convert the MBR to GPT and legacy to UEFI boot during restore using the Veeam KB.

[daystrom]

Hi ITP-Stan
But I don't think that applies when restoring from veeam agent. After you wrote, I think in another thread someone said agent will restore the system partitions as they were at backup time. I tried your method and it restore as MBR. I am pretty sure that even the original restore was via UEFI booted rescue media.

[ITP-Stan]

Never mind, my message is not that relevant and you seem to misread it anyways.