ESXi 6.7 is officially supported with Rapid Recovery 6.3. However, the newest ESXi 6.7 U2 hardware version 15 is not currently available as an export option in Rapid Recovery. If you need the exported VM to be hardware version 15, please export as a lower version and then upgrade the version within VMware prior to booting and using the VM.
If you experience an issue with Rapid Recovery 6.3 and ESXi 6.7, please open a service request with Support so we investigate.
For the latest information related to Rapid Recovery and VMware compatibility please review the System Requirements Guide and Release Notes located on the Quest Support site.