You have installed 2 NVIDIA 1080ti graphics cards and updated to graphics card driver version 390.xx and find that in ContextCapture settings the option to "Enable VulkanAPI and multi GPU processing" has become (greyed out) disabled.
This issue is curently being investigated by the Bentley ContextCapture development team. In the meantime you should revert to using the NVIDIA graphics version 388.43.Please see the link below to download this version:
Windows 10
Windows 7 and 8.1