Migrate BootCamp from iMac to external SSD

I recently bought WinClone with aim of migrating my existing BootCamp installation from the HDD on my 2015 iMac to an external SSD.
I’ve already installed Mac OS Monterey on the SSD successfully and created a MS FAT partition on the external SSD with Disk Utility.
WinClone finds the BootCamp volume and creates my BootCamp Transfer file about 590k but then seems to hang. I left it all night (8 hours) and nothing changed.
I’ve tried again several times but same result. The log file indicates that it reaches 3% complete and runs ntsinfo but then its Exit Status: 1 and nothing further happens until I cancel the create image from volume dialogue.

Log file:

2022-03-23T09:09:25Z:hiberfil exists…probing…
2022-03-23T09:09:28Z:We have Windows, but no BOOT folder, so checking to see if there is another partition on the same drive that has the folder. If so, we have a split boot config, and will grab the boot files
2022-03-23T09:09:40Z:Setting to not sleep…
2022-03-23T09:09:40Z:Writing Version of Windows to Image
2022-03-23T09:09:42Z:Could not read /dev/disk1. Probably due to SIP. Ignoring and returning 0x07
2022-03-23T09:09:42Z:Saving Filesize, 3.000000% complete
2022-03-23T09:09:43Z:Executing “ntfsinfo -m -f -f /dev/disk1s3”
2022-03-23T09:09:44Z:Exit status: 1
2022-03-23T10:49:58Z:Starting Helper Tool
2022-03-23T10:49:58Z:setting up listener for mach service com.twocanoes.WincloneHelper
2022-03-23T10:49:58Z:Getting new connection request
2022-03-23T10:49:58Z:Helper tool error: User Cancelled
2022-03-23T10:50:00Z:Setting the system to allow sleep…

end log file

Does anyone know what I’m doing wrong here?

Looks like there is an error getting info with ntfsinfo. This is probably due to NTFS errors. Try running chkdsk in windows on the disk1s3 windows partition.