Hi Romain,
I’m on 5.6.1 and I’m still having similar issues as the OP in that enabling bUseExperimentalVersion leads to a crash on startup.
I opened another thread about this here: Windows supported for CEF 128.4 shipped with Unreal 5.6.1?
It seems I have all the changes you linked here since they are a part of 5.6.1, so I must be missing something else.
I investigated a bit further and it seems the GPU process keeps crashing consistently as visible in cef3.log
[37552:45268:0917/123916.266:WARNING:chrome_main_delegate.cc(745)] This is Chrome version 128.0.6613.138 (not a warning)
[37552:45268:0917/123916.328:WARNING:account_consistency_mode_manager.cc(77)] Desktop Identity Consistency cannot be enabled as no OAuth client ID and client secret have been configured.
[37552:45268:0917/123942.935:WARNING:external_registry_loader_win.cc(232)] Error observing HKLM: 5
[37552:45268:0917/123942.937:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123942.938:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123942.938:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 1 time(s)
[37552:45268:0917/123952.725:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123952.725:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 2 time(s)
[37552:45268:0917/123952.726:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123953.877:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123953.877:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123953.877:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 3 time(s)
[37552:45268:0917/123954.726:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123954.726:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 4 time(s)
[37552:45268:0917/123954.727:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123956.084:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123956.085:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123956.086:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 5 time(s)
[37552:45268:0917/123956.851:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123956.851:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123956.852:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 6 time(s)
[37552:45268:0917/123957.732:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/123958.374:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/123958.375:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 7 time(s)
[37552:45268:0917/123958.376:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/124000.356:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/124001.144:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/124001.145:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 8 time(s)
[37552:45268:0917/124001.147:ERROR:network_service_instance_impl.cc(608)] Network service crashed, restarting service.
[37552:45268:0917/124001.845:ERROR:gpu_process_host.cc(1007)] GPU process exited unexpectedly: exit_code=777006
[37552:45268:0917/124001.845:WARNING:gpu_process_host.cc(1441)] The GPU process has crashed 9 time(s)
[37552:45268:0917/124001.845:FATAL:gpu_data_manager_impl_private.cc(436)] GPU process isn't usable. Goodbye.