Hi
I'm not using Wintoolkit, I integrate them from the command line.
You are right, it is difficult to track down what is causing the SFC problem, but I'll keep testing and post back anything significant.
Kind regards
I´ve found some reports about problems with kb3126587 and kb3126593, hope it helps.
http://www.tigercomms.com/news/microsoft-windows-updates-kb3126587-and-kb3126593-which-were-released-9-february-2016-are,
https://social.technet.microsoft.com/Forums/en-US/1016c38f-20cc-418c-a0df-af8091b1d9f5/kb3126587-and-kb3126593-install-fails-with-error-80070026?forum=w7itprosecurity,
https://social.msdn.microsoft.com/Forums/vstudio/en-US/2ecfef80-cd3d-4e03-985c-cb2b523a00e9/issue-with-kb3126587-kb3126593?forum=netfxsetup