I’m also experiencing the same problem (Femto Mega) and haven’t found a solution yet.
I also connect to a PC via a thunderbolt port and I also see the cameras in the the Device Manager:
The error message I get is
2023-11-09 11:34:53.594 INFO [18444] [loggerInit@18] **********************************************
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@19] OrbbecViewer launched! Welcome!!
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@20] - Version: V1.8.1
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@21] - Author:
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@22] - E-Mail:
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@23] - Company: orbbec
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@24] - Website: http://www.orbbec.com.cn/
2023-11-09 11:34:53.595 INFO [18444] [loggerInit@25] **********************************************
[11/09 11:34:53.796622][info][18444][Context.cpp:67] Context created with config: C:\Users\Me\Documents\Research\OrbbecViewer_1.8.1_Windows\OrbbecSDKConfig_v1.0.xml
[11/09 11:34:53.796688][info][18444][Context.cpp:72] Context work_dir=C:\Users\Me\Documents\Research\OrbbecViewer_1.8.1_Windows
[11/09 11:34:53.820221][error][18444][WinHelpers.cpp:522] CreateFile failed
[11/09 11:34:53.820322][error][18444][WinHelpers.cpp:557] could not find camera in windows device tree
[11/09 11:34:53.824241][error][18444][WinHelpers.cpp:522] CreateFile failed
[11/09 11:34:53.824353][error][18444][WinHelpers.cpp:557] could not find camera in windows device tree
[11/09 11:34:53.828302][error][18444][WinHelpers.cpp:522] CreateFile failed
[11/09 11:34:53.828408][error][18444][WinHelpers.cpp:557] could not find camera in windows device tree
[11/09 11:34:53.846991][info][18444][DeviceManager.cpp:15] Current found device(s): (0)
[11/09 11:34:53.847073][info][18444][DeviceManager.cpp:307] Enable net device enumeration: true
[11/09 11:34:54.855518][info][18444][DeviceManager.cpp:15] Current device(s) list: (0)