As documented by this tweet from Brian Hailey, PE, Windows 10 v1803 update breaks Hydraflow in Civil 3D, specifically the output from the application.
WARNING! Windows 10 update breaks Hydraflow!
More info -> https://t.co/XJOtisCRes
If you use the Hydraflow extensions, check your results and your Windows version. If you Have Windows 10 v 1803, revert back to a prior version.
How to revert -> https://t.co/aImNCeHfC9— Brian Hailey, PE (@C3DPlus) June 6, 2018
Please verify your version of Windows if this could be a problem for you.
