This error appeared during the first phase of an in-place upgrade from Windows 8.1 to Windows 10. The error refers to the Windows 10 setup.exe exit code and was found in the smsts.log file.
Windows Setup failed with hexadecimal exit code 0xC1900208 (decimal 3247440392)
According to Prajwal’s article on this error, the cause could be an incompatible app installed on the old operating system. The approach to check this is to mount the Windows 10 ISO in Windows 8.1 for example, and run a custom setup command. I tried the command on Prajwal’s blog but it kept reporting invalid parameters, so I stripped it down to ‘setup.exe /Compat ScanOnly’ which presented the GUI. I stepped through a couple of pages before it performed the scan and presented the list of incompatible apps.
Removing this particular app wasn’t straightforward as it required a ‘release code’ before eventually uninstalling. Following uninstall, the Windows 10 build ran successfully.