Created on: June 19, 2017
At the time of this writing, based on information provided to us by Carbonite, we can confirm that their online data backup services do not support storage devices connected via Thunderbolt, Thunderbolt 2, or Thunderbolt 3. Additionally, wireless storage devices are not supported. Storage devices connected by USB are supported.
Note: if you must use Thunderbolt-connected devices with an online backup service, you may want to try Backblaze.com. Neither Carbonite.com nor Backblaze.com are affiliated with MacSales.com, and their services are not supported by MacSales.com. This information is provided strictly as a courtesy.