Cloning - wrong drive letter to boot?

I have cloned in the past using EaseUS Todo backup successfully.

For the most recent clone I used Macrium Reflect, and noticed the cloned system drive had a drive letter (E:, the next available one). The clone refused to boot. But EaseUS always gave it A: or B: and on booting it, it became C:. The failed boot said it couldn't find some system file or other, and gave a path beginning \windows, with no drive letter.

Why is Macrium doing this? And is it what causes the problem? In the future I will remove the drive letter in disk management, assuming this might help.

I thought this problem went out with Windows 95 ish.

If it means anything, the failed boot was a computer using BIOS booting, not UEFI.

By default, C drive letter assigned to booted Windows installed partition if the operating system not booted then it does not matter which drive letter it gets as Windows Boot Manager don't boot operating system based on drive letter assignment.

Also give us the error message so we can help you.

In the past I had a problem if I booted the machine I produced the clone on again, with both disks in. It would call one of them D: and it wasn't bootable when put into another machine (before rebooting, the clone had no letter). I assumed that problem went away with newer versions of Windows.

You refer to Windows Boot manager. Is that not only for UEFI? I had the problem on a non-UEFI machine.

I can't remember the exact error message. I ended up doing a fresh install on the computer I was trying to clone to. All I remember was it couldn't find an important system file and it referred to it by a path beginning with \windows, with no letter.

Windows Boot Manager (BOOTMGR) can be used for BIOS and UEFI firmware.

If it can't find winload.exe then the cloning program you used probably failed to set the correct entry in the bcd store.

should be fixable with bcdboot command.

From your working windows open an admin command prompt and type

bcdboot e:\windows /s (whatever is the drive letter of the active partition on the cloned disk )

then press enter

Another possibilty is that your cloning program didn't change the disk signature on the cloned disk.

FreeBooter said:

Windows Boot Manager (BOOTMGR) can be used for BIOS and UEFI firmware.

What Is Windows Boot Manager and How to Enable/Disable It - MiniTool

What is Windows boot manager and what role it plays in your computer? This post will introduce you the BOOTMGR and methods to enable and disable it.

www.minitool.com

Click to expand...

winload.exe, that was the file it couldn't find. So it had got far enough to look for it. I was getting a windows error message, so the initial boot sequence must have run. It would appear the boot manager wasn't looking in the right place for winload.exe because it wasn't on C:.

I've never disabled windows boot manager, so I assume it was enabled. It was Windows 11 Pro installed on a Dell R410 server, dual X5650 CPUs, with the BIOS set to non-UEFI (I forget why, but I had trouble with UEFI so switched it off to allow the install). I have two almost identical computers (the other is an R510 board, but same CPUs), one got a failed SSD, so I tried to clone one to the other.

SIW2 said:

Probably hasnt set the correct entry in the bcd store.

should be fixable with bcdboot command.

Click to expand...

You mean Macrium forgot a step? Why would it do that and not give an error message?

I tried various fixes, and I'm sure one was bcdboot.

I tried various fixes, and I'm sure one was bcdboot.

Click to expand...

You might not have done the bcdboot command right. There have been several reports with clones not booting by that particular program.

A disk sig collision is also a possibility if the cloning program results in both the source and target disks having the same sig. Windows will change the sig of the second disk brought online and there are consequences to that. Both the bcd entry and the os drive letter alias reference the disk sig.

What I found odd was as soon as the clone completed, a windows explorer window opened up with the cloned drive. That never happened with EaseUS. Was windows doing something to it when it should have been left alone until the next boot?

It also makes no sense Macrium can make good clones for some people and not others.

Macrium works differently, when I used EaseUS (and why I stopped using it), if I wrote a lot of data to the disk being cloned, the computer would crash. My system disk gets written to a lot with Boinc (science distributed computing calculations), and my data disk gets written to a lot from the security cameras. With EaseUS I had to pause those while cloning.

I'm going to try some tests at some point. I'll try a UEFI and a non-UEFI machine, both letting it do what it wants and removing the drive letter before reboot, and with Macrium and EaseUS. See what I can come up with. I'll try to remember to report back here.

Lamberto Vitali said:

I'm going to try some tests at some point.

Click to expand...

There's a tool on the Macrium bootable Rescue Media called: Fix boot problems.
Whether you clone or restore a backup to a different drive... if it doesn't boot... try running that tool.

It won't make anything worse, but it may fix the problem.

removing the drive letter before reboot

Click to expand...

What is the point of that?

SIW2 said:

What is the point of that?

Click to expand...

Because I assume the problem is Windows looks on C:.

Ghot said:

There's a tool on the Macrium bootable Rescue Media called: Fix boot problems.
Whether you clone or restore a backup to a different drive... if it doesn't boot... try running that tool.

It won't make anything worse, but it may fix the problem.


View attachment 68875

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Thanks, I'll add that to my test if and when I have time. I really would like to know how Windows screwed up a simple boot. One drive in the computer, no choice to make, look on the only one! And to be able to load the error message, but not find itself on the same disk?! Only MS could be that monumentally useless.

Lamberto Vitali said:

Only MS could be that monumentally useless

Click to expand...

Wise words. ^^

Lamberto Vitali said:

Because I assume the problem is Windows looks on C:.

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bcd stores the info as disk id and partition id.

something like this:
PartEx 3900000 HD MBR Sig:165938e4

or for gpt

PartEx {6e277fa6-aa82-4939-b7e4-1cb049271596} HD GPT Sig:{fa75f1bd-5ec8-4fa2-98c8-e124d85014cd}


It is dificult for humans to work with those strings of numbers , so windows displays to you an alias. Either a letter or a symbolic device path.

The letters it shows are not consistent across different os which confuses a lot of people.

That is why when you are booted into your os on disk 0 partition 3 it displays that as C.

But when you boot into a different os it displays disk 0 partition 3 as a different letter.

Whatever letter is assigned by your currently booted os ( or winpe ) is only in the registry of the currently booted os ( or winpe ). Removing or changing it there has no effect on the registry of any other os.

SIW2 said:

bcd stores the info as disk id and partition id.

something like this:
PartEx 3900000 HD MBR Sig:165938e4

or for gpt

PartEx {6e277fa6-aa82-4939-b7e4-1cb049271596} HD GPT Sig:{fa75f1bd-5ec8-4fa2-98c8-e124d85014cd}


It is dificult for humans to work with those strings of numbers , so windows displays to you an alias. Either a letter or a symbolic device path.

The letters it shows are not consistent across different os which confuses a lot of people.

That is why when you are booted into your os on disk 0 partition 3 it displays that as C.

But when you boot into a different os it displays disk 0 partition 3 as a different letter.

Whatever letter is assigned by your currently booted os ( or winpe ) is only in the registry of the currently booted os ( or winpe ). Removing or changing it there has no effect on the registry of any other os.

Click to expand...

So because I had the problem on a non-UEFI machine, presumably I had something like "PartEx 3900000 HD MBR Sig:165938e4".
So what should have happened is Macrium changed that to something else (so there weren't two identical disks at once) and updated the pointer to it?
If it's not updating the pointer, how come it works for some people and not others? Something must be stopping it a lot of the time, you'd think they'd fix it.
And why doesn't windows just have a look around for any installations if the pointer is wrong? Jeez, even the self repair in Windows didn't fix it.

Yes because the cant find winload message tells you either the bcd entry is wrong ( or winload is damaged /missing which is unlikely).

It might not be only the bcd entry there could be other issues. We dont know because you havent got that far.

But it's loaded lots of windows already, it's accessing the right disk (the only disk) to produce the error message. It even lets me load it's absolutely useless repair tools. So how can it possibly not find the rest of itself? There's only one disk to choose from. And if there were two, it could ask!

It finds a wrong BCD entry, so it should read every disk, decide which ones have windows on them, and change the pointer (possibly asking the user). The repair tools should most definitely be able to do such a simple thing.

It would be like an address telling you to go in the house on the left on a road with no other houses. But all you find is a house on the right. If you were Windows, you'd just sit down and die. A sensible approach would be to try that only house, or phone up the person who gave you the wrong address. We're up to version 11 and they still haven't mastered the simple art of starting.

I guess I just go back to EaseUs, less people seem to complain about it. I can't even complain to Macrium without buying it. And I ain't buying it unless I know it works!

This is why I stopped trying to use the clone option. I always make a system image and it has always worked when I needed to use it.

The trouble with an image is you can't get files from it. The thing I use backups for most is to restore an accidentally deleted or overwritten file.

Also, you can't boot an image. How would you get a bootable drive from it? You'd need to install the OS first, then.... would it let you overwrite it?!