Can I boot a windows computer from a Windows startup drive on USB?

Yes. I've searched this for you:
Windows 10 Tutorial Index
(Worth bookmarking)

to find
Create Bootable USB Flash Drive to Install Windows 10

What can you do with it?
Boot to Advanced Startup Options in Windows 10
See Option 5

And of course you can use a live boot disk with loads of utilities on it and a normal Win 10 environment:
Win10XPE - Build Your Own Rescue Media

In addition...

Boot from USB Drive on Windows 10 PC

I've successfully tried it with external USB 3.0 HDD's loaded with Windows 10.
The OS will self-configure.

antonio3535 said:

Thanks for that, I'll came to you when I test it. My idea is to have a bootable Windows 10 USB SSD that I'd use to boot any desktop/laptop for testing purposes. So you say this is possible?

Well, you have to know how to do it.

The process can be very confusing. Sometimes a standard USB Flash drive is much better for a quick test!

So here we go... Remember to backup your entire system, first!

If you are using a bare HDD or SSD, a special cable will be needed for DC power and data. Here is one that I have bought recently and works very, very well:

https://www.amazon.com/UGREEN-Cable-.../dp/B00MYU0EAU

Here is a simplified overview that I use -

1) After shutting down, disconnect your boot drive and plug in the bare SSD or HDD instead.
2) Install Windows 10 and anything else on it, via a prepared USB Flash Drive or DVD.
3) Reboot, test and then shut down.
4) Remove the "bare" drive and reconnect your original boot drive.
5) Boot and test to ensure that your original system is OK.
6) Shut down.
7) Connect the newly prepared drive with the special cable (and power) to a free USB 3.0 port.
8) Disconnect any other USB mass storage devices.
9) Power on.
10) Boot while holding down the appropriate function key to selectively boot from the System BIOS - usually F9 or F12.
11) Select the USB drive to boot with - not the Network or CD/DVD drive.
12) The newly prepared HDD or SSD should boot slowly, but normally. Be patient. There will be some auto-configuration.
13) Login. Test functionality and then shut down.
14) Unplug the DC power adapter cord. Then disconnect the power/data interface from the bare drive.

That's it.

One more thing, if you use an SSD or 3.5 inch HDD, supplementary power will be needed from the cable's AC Adapter. If it's a 2.5 inch HDD you won't need it.

Please post back with your results.

Hope this helps you.

antonio3535 said:

Thanks for that, seems very useful Excuse me, before I give it a shot:
- I guess that bootable drive may not always work on other PCs/laptops as they may have very different hardware (unlike macs that are quite similar hardware-wise)?
- If I use an SSD for that, shouldn't it boot quite fast if I use USB 3.0 or a newer USB-C caddy (on newer computers)?
- Shouldn't a 2.5 SSD be OK without the DC power adapter?

Hi again -

For your first question - It depends. Windows 10 might have the drivers it needs to achieve minimal function.
For your second question - Faster than a USB based HDD, yes, but nowhere as fast as the internal interface SATA connection. It is very technical.
For your third question - It should, but the DC adapter comes with it, just in case. The USB 3.0 port has enough power, but you are using a special interface with it.

I wish that I could be more definitive - again, it should work, but there are always exceptions, lol.
I never tried the SSD without the AC adapter - I'll need to test it to be sure.

Hope this helps!

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