Tried to make a Windows 10 BootCamp image and got this error.
It makes a file, small in size.
When Winclone start an operation, it changes the permissions on the disk to allow writing through a helper tool. It seems like something is blocking this. Do you have any software (antivirus, security) that could be blocking it?
Got it to work. It was Norton 360. Had to add Winclone to the list of allowed apps.