Etcher 1.4.4 working fine.
Then installed Ext2Fsd 0.69 from SourceForge
Ext2 File System Driver for Windows download | SourceForge.net
Etcher now hangs, uninstall Ext2Fsd and Etcher works fine.
Windows 10x64
During development want to be able to quickly make a change to an ext3 partition on the SD card without having to wait while etcher rewrites the whole card.