Boot Runner has been updated to support High Sierra. This support article covers the changes in Winclone 6 to support High Sierra:
Support for APFS
APFS is new filesystem that replaces HFS+. APFS also replaces the volume manager from Core Storage to APFS. Boot Runner 2 was updated to recognize APFS volumes as bootable Mac volumes and allow this volume to be selected in Boot Runner as a startup volume.
No Mac Startup Volume
If you did not upgrade Boot Runner prior to upgrading to High Sierra, you may not be able to select your Mac volume since it will not be recognized as a valid startup volume. To resolve the issue:
1. Reboot the Mac and boot into safe mode by holding down the shift key at the startup chime.
2. Boot Runner will be show when the Mac is in safe mode. Sign into the Mac, and delete Boot Runner.app from /Library/PrivilegedHelperTools/.
3. Reboot the Mac and verify that Boot Runner no longer starts up.
4 Install the latest version of Boot Runner 2.