Bootcamp Clone on external doesn’t work

I bought Winclone this morning with the intent of cloning a bootcamp partition to and external drive. I am having no luck.

I’m using the following:
2018 Mac Mini with Catalina
Windows 10 Professional (Oct 2018)
Samsung Evo 840 with a SATA to USB-C adapter

The process appears to work as advertised, but when I restart to the cloned Bootcamp partition, the computer boots to a black screen, then eventually shuts down. I never see the apple or Windows logo.

A few notes:
-After the clone process, I have to use the Make EFI bootable option

  • The restored image is only 1/2 the size of the original (9 GB vs 21 GB). I’m referring to the actual usage of the partition, not the image file, which I know is compressed.
  • SIP and boot security are disabled/ no security
  • The only way to boot back into anything is through recovery mode-
  • The bootcamp partition was created on Catalina (e.g. not upgraded from Mojave)

Any suggestions?


On the new T2 Macs, you need to turn on external booting:


That was the first thing I did. I’ve spent all weekend trying to get this to work. Finally got to the point where windows blue screens with an Inaccessible boot device error message. Followed the instructions at, but that did not resolve the problem.

Unfortunately, this was not the turnkey solution I was hoping for. Would it be possible to get a refund?

I’m having the exact same issue. Please assist!

I am also having this issue. I bought this program just a few hours ago. I am on a Mac mini 2018, Windows 10 Home, using a Samsung X5 thunderbolt 3. Since it is a T2 Mac, I disabled that. I made sure that it can be booted from an external drive. I also disabled SIP.

The original bootcamp on the internal drive works fine. But trying to boot with the external drive just gives me a blue screen that something went wrong. I hope there is guidance given, otherwise I agree that a refund should be considered.

External booting can be tricking. We do test it in multiple different scenarios to verify it does work with modern hardware and Windows 10, but it doesn’t always work. If it doesn’t work for you, please request a refund at :

Ok, I haven’t quite given up yet. I figured out that when I restarted after Sysprep, holding down the option key was not working, and for whatever reason the my Mac Mini was booting with a black screen…no Apple logo and no Windows logo and nothing would work until I booted in recovery mode. I finally figured out that after running Sysprep and shutting down, I need to immediately start up in recovery mode. I was then able to clone the bootcamp partition and restore to the external drive.

Now when I boot the the restored drive, windows actually starts to boot with a message that it is preparing the system. However, the boot eventually fails, and I’m left with a variety of options to restart in safe mode, safe mode with command prompt, etc. the next reboot fails altogether.

Now that I can get to this point, what is the best course of action?

Is there any message about way it failed? Did you try a safe boot and see if that works?

Could I be presumptuous and suggest the importance of us Sysprep before attempting to create an external drive, even if it is to be used on the same machine?

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