WincloneHelper[1455] / Error Creating EFI File

Hey there,

Trying to clone my Windows 10 bootcamp machine on High Sierra MBP. Pick source (bootcamp partition 100gb), select destination new Western Digital 2tb hd. Process gets to approximately 90% complete, then states…

2018-01-16 10:43:34.331376-0500 localhost com.twocanoes.WincloneHelper[1455]: Error creating /Volumes/BOOTCAMP 1/EFI/Microsoft with error You can’t save the file “Microsoft” because the volume is read only.
2018-01-16 10:43:34.331665-0500 localhost Winclone 6[1273]: Error Error Domain=WincloneHelperError Code=6 “Error Creating EFI File” UserInfo={NSLocalizedDescription=Error Creating EFI File}

Any idea whats causing this?


This is usually cause by security software preventing writing to the EFI partition. You can test by running this in the terminal:

diskutil mount disk0s1

and then you will see a volume mounted on your desktop. See if it is writable.


I actually get a…

Volume on disk0s1 failed to mount
If the volume is damaged, try the “readOnly” option

Odd- the Windows VM boots just fine.

Windows VM doesn’t use the EFI partition to boot, I don’t believe. I believe reinstalling macOS will repair it, but not sure that you want to do that.