I have Windows 10 Pro installed on a external flash drive, I tried to install Windows via bootcamp but it is required to have more free space. I succeeded to install Windows 10 with VirtualBox on a SanDisk 32 gb flash drive and boot into Windows 10. The drive capacity is too small so I bought a Kingston Kyson 64 gb USB 3.2 flash drive, but it will not work with Bootcamp.

If I fresh install Windows with VirtualBox, the installation process will stop around 40% and reboot to EFI interactive shell.

If I clone SanDisk > Kingston from another Bootcamp machine, the clone drive will boot to Windows loading screen followed by BSOD.

If I clone SanDisk > Kingston from the booted Windows 10 drive, the clone drive will boot to Windows loading screen followed by Startup blue screen.

If I clone sector-by-sector, the clone drive will boot with BSOD 0xc0000225, 0xc000000e, Missing / Damaged Winload.efi.

  • In all cases I’m always booting Windows from Option (⌥) or Alt Startup Manager. I used VirtualBox only to install Windows 10 on a external disk, and succeeded to do so on the SanDisk 32 gb flash drive. – flavoral Feb 6 at 8:04
  • Windows really doesn't like being booted from an external drive, even on a regular PC. You need WinToGo for that to work properly (which I think MS have just abandoned as a product) – Tetsujin Feb 6 at 8:21
  • Is the drive faulty? – Thorbjørn Ravn Andersen Feb 6 at 8:21
  • This is outside my area of expertise really, but have a look at twocanoes.com Basically, if it can be done, it can be done with something they make. Some of their tools are free, but not the main Winclone. – Tetsujin Feb 6 at 8:24
  • Humor me. Install the SanDisk in the USB port and post the output from diskutil list. – David Anderson Feb 6 at 16:37

IMO, flash drives are not designed to endure the amounts of writes that would be performed by having an operating system installed on the drive.

There are many different mechanisms which can be referred to as having cloned. Since you have not explained how you cloned Windows 10, I will assume you are confident Windows 10 was correctly cloned. Windows does have the ability to detect when being cloned and if detected, can result in Windows 10 not booting properly. The general solution to this problem is to rebuild the BCD.

I realize this answer is vague, but this is only do to the lack on details in your question.

  • EaseUS Todo Backup and WinToUSB will end both with the same results. I tried cloning in Legacy, VHD, VHDX and sector-by-sector modes. I am trying to restore in Command Prompt from booted Install DVD. I know it is not recommended but with SanDisk flash drive Windows 10 is more than fine. – flavoral Feb 6 at 16:37
  • If you can boot from a Windows 10 install DVD and open a Command Prompt, then why not just enter the commands to install Windows 10 on the kingston drive? Avoid cloning all together. – David Anderson Feb 6 at 16:51
  • Yes please, I will install it this way but I am missing the commands. Also I tried all other commands such as BCD..., CHKDSK, SFC and registry hacks from the working Windows 10 external drive with no success. – flavoral Feb 6 at 18:41
  • I have a few thoughts. How old is your Mac? What model? I ask because you can use DVD's. I think the kingston is a Type A 5 GB/s (USB 3 = USB 3.1 Gen1 = USB 3.2 Gen 1) drive. Is this correct? What about the SanDisk drive? What did you have the virtual machine set for USB? USB 1.1, 2.0 or 3.0? – David Anderson Feb 6 at 18:49
  • The main is an iMac (21.5-inch, Late 2015) with internal Bootcamp and the one in question is a MacBook Air (Retina, 13-inch, 2019) with external SuperDrive and Bootcamp. The SanDisk is a Ultra Fit USB 3.1 and the Kingston is a Kyson USB 3.2 Gen 1 with reading up to 200 MB/s. – flavoral Feb 6 at 20:41

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