I am trying to run the Cloud Mirror sample app in Windows Sandbox, and I get "Could not register the sync root, hr 801f000f".
The error code appears to correspond to ERROR_FLT_DO_NOT_ATTACH
described as "Do not attach the filter to the volume at this time."
It is hard to determine which APIs are and are not available in Windows Sandbox. Seems like the Cloud Files APIs rely on NTFS filter drivers and you can't add them to Sandbox?