I have a Dell Inspiron 15 - i7559 laptop with windows 10. I just did a disk clone (including all OS and files) following this youtube video. The cloning was done with Macrium Reflect. After disk cloning, I have to boot my laptop using the rescue disk (a USB key) created with Macrium Reflect. In the video, it says to press F12 key at rebooting to make this menu appears and select the second option (it shows a CD, but could be a USB as well): enter image description here

But when I press F12 key, nothing happens. Basically, I was looking for the UEFI boot option in my BIOS, and was not able to find the option to boot with my USB key. The boot option does not show that I can use my USB key. I did some research, and maybe I could disable secure boot option to be able to boot from the rescue media in my USB key, and when I try to turn that setting off, it gives me a warning message "you might need to reinstall your OS system...`. How do I use one-time boot with my USB key and complete the last step of my disk cloning?

Here are my BIOS pages: enter image description here enter image description here enter image description here enter image description here

Edit: I found out the true problem with my laptop: There was a bug with Dell on their BIOS. Normally the Dell logo would show up during startup. But this bug makes it unable to show, thus unable to access the boot options. I did reset my BIOS cell clock by unplugging it and replugging it. Then I could achieve the one-time boot menu by pressing F12 during startup.

  • 1
    I think you need to modify your Boot Option Priorites on the Boot tab. See if you can select USB as #1 and WIndows Boot Manager as #2. Feb 16, 2021 at 19:04
  • Start tapping F12 continuously before the Dell screen appears. If this doesn't work, use the F2 key to enter the BIOS/UEFI configuration and set the boot order. However, I find this very suspicious: If the cloning was done correctly, you should have been able to boot directly into Windows without any rescue disk. Why are you using the rescue disk? Has something gone wrong with the cloning?
    – harrymc
    Feb 16, 2021 at 21:07
  • @harrymc Well, I finished the disk cloning, and as I am writing from the current disk. Booting with a rescue disk is a suggested step in the Youtube video I followed, since I did the disk cloning with Macrium Reflect. The video says to boot with the rescue disk created with Macrium Reflect, and fix a boot problem after cloning, which I still yet to figure out how to do.
    – Chen
    Feb 17, 2021 at 0:23
  • I haven't followed the video, but it must be doing it wrong. Try another product, for example AOMEI Backupper Freeware to do Cloning.
    – harrymc
    Feb 17, 2021 at 7:20
  • First thing you should do is to do what @Keith Miller says. Feb 21, 2021 at 11:03

4 Answers 4


I haven't followed this youtube video, but it must be doing it wrong. Successful cloning should mean that you could physically replace the old disk with the new one, and after boot everything will work exactly as before. No boot from removable media should be necessary,

If you wish to use Macrium Reflect, you could instead study the official video found at their website in Cloning a disk using Macrium Reflect 7. An article detailing the same method, with screenshots, can be found at How to clone your PC hard drive using Macrium Reflect.

If you still have problems, you could try another product, for example the free AOMEI Backupper Freeware. The Cloning method is described in an AOMEI article, with screenshots.

  • Seems like I don`t need to do the rescue media step. That last one is not necessary. I asked Macrium Reflect support team, and they confirmed that to me as well.
    – Chen
    Feb 22, 2021 at 23:30

This behavior is similar with that you change the EFI boot to UEFI after cloned your disk (please, give me feedback if it´s right); if this right, please, try change your setup from UEFI to EFI (or Legacy) and renew the usb steps.

  • Ok, so you are saying to change UEFI to EFI? Then what to do afterwards?
    – Chen
    Feb 16, 2021 at 15:37
  • UEFI is the same as EFI - EFI is the standard and UEFI is the implementation.
    – harrymc
    Feb 16, 2021 at 20:57
  • Mentioned EFI Legacy, UEFI is newer. As mentioned in my response, doing again same steps. Feb 17, 2021 at 13:14
  • UEFI is the new replacement for BIOS. An EFI layer exists between the firmware and the operating system, practically, efi is a name/label of the partition where UEFI boot files are stored. Feb 22, 2021 at 19:48
  • Boot files and BOOT are two total different things. While BOOT and UEFI is the first program installed in the hardware the machine will execute. Then MBR and EFI are the boot files, (in the case of EFI it requires an extra partition layer while in MBR there's installed few extra codes in the beggining of partition)in which will be required in order to start the OS. Feb 22, 2021 at 19:53

I spent one year making 300 experiments with BOOT and UEFI in diverse machines so I'll do my best bet here:

One of the reasons I remember of USB not showing up it could be:

  1. USB model-company, try to use different USB stick, Kingston, SanDisk and with different sizes first try 4GB, then 8GB, then 16GB.

4GB is the fail safe here, and notice that not all USB models are meant for booting.

  1. I know that once or twice deactivating Secure Boot may help install Ubuntu, or do other tricks but that's it. I still don't believe is the problem here.

  2. Simply as it is, your UEFI isn't compatible with doing such things. For this reason I always tested my pen drive with multiple machines.

  3. Make sure you USB installation was meant for UEFI, try to change Boot list to Normal Boot and see if your USB driver appears, (make few reboot attempts). If it shows up is because it was configured for Normal Boot.

And it's strange that is says that if you deactivate Secure Boot you may need to reinstall Windows. It could be new type of computers or am I getting too old? Sometimes it would say such things but nothing will happens at the end, it depends and I wouldn't be risking if you don't have a backup plan.

  • I already disabled secure boot. Still no clue how to do this.
    – Chen
    Feb 21, 2021 at 16:38
  • Before trying another USB stick, go to Boot Options List > Boot Option #1 > <ENTER> > AND TRY TO SELECT YOUR USB DRIVER Feb 22, 2021 at 18:05
  • Then, if didn't appears change your USB stick model, company and try another one. Secure boot has nothing to do with anything here about driver not showing up! Feb 22, 2021 at 18:07
  • that made my laptop unable to boot anymore ..
    – Chen
    Feb 22, 2021 at 18:42
  • None that I've said was capable of making your laptop unable to boot! You should be more clear in the steps. We do not have your screen. So were you able to select USB form boot list? Did it showed up? Feb 22, 2021 at 19:35

First, a few things to keep track of.

Disks (harddrive, SSD or USB) can be partitioned in a few different ways. MBR (Master Boot Record) was the most common way until Windows 7, currently GPT (GUID Partition Table) is the most common.

UEFI boot requires GPT. UEFI can boot MBR disks but needs a special compatibility mode often called CSM (Compatibility Select Modules) or sometimes just "Legacy boot".

If you are not sure which partition type your drive has then you can check from a working computer or install disk using the diskpart tool. Open CMD and type "diskpart" and press Enter, then type "list disk" and press Enter. The right most column shows if the disk is GPT.

Now, about cloning. A few things are worth mentioning. Automated cloning tools are good but make sure it is a tool that can clone a system drive. Some can only clone data partitions and skip the actual boot partition.

A good tip is that many storage drive vendors have cloning tools for free on their websites. Just make sure at least one of your drives is from that vendor.

Fast startup which is a feature in Windows 10 can cause trouble when booting cloned drives so turn it off before cloning. Or at least hold Shift while restarting Windows 10 to temporarily disable it once. When your computer has booted up it will be on again.

Sometimes you need to recreate the boot partition after cloning if the cloning software messed it up. Create a FAT32 partition of at least 500MB, preferably at the very beginning of the drive. Assign a drive letter (V in my example) using the diskpart tool in CMD.

Boot a Windows install disk and press Shift+F10 to open up CMD. You may need to click Next a few times before Shift+F10 will work. Then:

list disk
sel disk 0
list part
sel part 0
assign letter V

the above list of commands assume that you have one drive and that the boot partition is the first one.

Now you need to run the bootsect command: https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/bootsect-command-line-options

Usually something like this:

bootsect /nt60 V: /force

Note the V: for the drive letter you set earlier using diskpart.

To add your Windows partition to the new boot list use BCDBoot: https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/bcdboot-command-line-options-techref-di

bcdboot C:\Windows /s V: /f ALL

Once again the V: depends on if you followed the previous instructions. Also note that if you run this command from a Windows install media then the Windows drive may not be C:

An optional way to rebuild the BCDstore is this: https://support.microsoft.com/en-us/topic/use-bootrec-exe-in-the-windows-re-to-troubleshoot-startup-issues-902ebb04-daa3-4f90-579f-0fbf51f7dd5d

Good luck! It is a bit messy but it usually gets there in the end.

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