Question Can one boot Win10 from an external HDD connected by USB?

britechguy

Notable
Jul 2, 2019
1,473
233
1,190
47
Some of you have probably been following the saga, How to gain access to files/folders on a drive that originated from another machine . . .
For those that haven't, it's the backstory for the question that follows.

I obviously know that you can boot from USB flash/thumb/jump drives and have done so many times in the past. But I seem to recall that this will not work for an external USB HDD, like a typical external USB backup drive.

I am getting desperate enough that I'd like to try booting from the HDD that had been the boot device in a now-defunct machine on the new machine, just for the purpose of getting access to data I can't seem to get any access to via every conventional method I know of. But I'd really, really prefer not to have to actually transplant that drive in to the new machine, but would prefer to just change the boot order and tell it to boot from USB and have it use that old system drive that's connected via USB cable be the boot device. Since it was the OS system drive, all the bits necessary for it to be a system boot drive are already there.

Can this be done?
 

britechguy

Notable
Jul 2, 2019
1,473
233
1,190
47
Unfortunately, the new machine is Home.

But I am not talking about Windows To Go, which is a thing of its own that I actually know about.

This is about booting from what had been the full blown Windows 10 OS drive on a machine whose motherboard failed, connected to the new machine via USB cable, using it as a USB boot device. I just don't know if that can work. I know I could transplant it, as this has been discussed many times on this very forum. If it boots that way, I could extract the data to an actual external USB backup drive. But I would really like to avoid doing that actual transplantation if I can avoid it.

I'm also aware of the limitations of "booting from transplanted drives." My one and only concern here is just getting the darned old user data copied off that drive so that we can copy it on to the new machine.

The whole situation is perverse!
 

britechguy

Notable
Jul 2, 2019
1,473
233
1,190
47
True, that is absolutely an option and probably the best one to exercise.

I would like to know if what I asked about is even possible to do, though, as it was not at one time.

I also sometimes try to walk people (generally very sophisticated users) through doing things strictly via Windows, which is another reason I ask.

I definitely think the next practical step for actually extracting that data is a live Linux boot and copy. Thanks much for the suggestion. Frustration can sometimes cloud judgment, and in this case it has had that effect.
 

Colif

Win 10 Master
Moderator
i saw a way to clone an install onto an external drive but this is in fact the opposite of that, its use a external drive to boot.

Have you tried? If you copy all the valuable info off drive before hand, no reason to not try.

what motherboard is in PC you want to attach it to? some let you set all USB as live at boot so that it will check them at same time as it loads kb/mouse. If you were to attach hdd and have USb as 1st item in boot order, it might work.

Do you know if drive is formatted as MBR or GPT?
 

britechguy

Notable
Jul 2, 2019
1,473
233
1,190
47
No, I have not dug in to how things were set up on the old hardware.

At this point I will go the live Linux route if the last ditch attempt noted in the other thread does not result in access being granted.

All I want is to get this guy's old user data copied off his old drive for him. Never has this been the production number this particular time has turned in to!
 

USAFRet

Titan
Moderator
Mar 16, 2013
112,935
1,813
155,140
18,534
Take a previously internal drive with OS, put it in an external USB enclosure, and try to boot from it?
I've never seen that work.

And I've tried it a time or two (not lately, though). Simply does not work.
 

britechguy

Notable
Jul 2, 2019
1,473
233
1,190
47
Simply does not work
Which is precisely the answer I was looking for, if not hoping to get. If I decide to experiment with doing this "just for the heck of it" I will report back on how it went for me. I will be disposing of the client's equipment, and will secure his permission to do this experimentation before wiping (or physically destroying) that drive.

There are certain things that seem to get changed that "fly below the radar" and that surprise you when you try something that was impossible in the past, only to find it works. That's not what I'm expecting here, really, but I may do it just to satisfy my curiosity and to confirm the state of affairs you've reported as of this time.
 

USAFRet

Titan
Moderator
Mar 16, 2013
112,935
1,813
155,140
18,534
There are ways to sort of do it.
I believe Macrium Reflect has some function to convert a drive like that.
Never tried it, though.

But just plugging a drive and hoping it works?
No.

Bad enough just trying to do it internally, much less through USB.
 

ASK THE COMMUNITY