Are you running this on a relatively new system? Do you have a graphics card installed?

I haven't updated OpenTK in a bit, I know some older versions have issues actually loading drivers and instead try to use the ancient OpenGL implementation that Windows ships with, which could be the problem here. To diagnose, can you please add this line into ExampleWindow.cs, line 126 (between base.OnLoad(e) and InitializeOpenGL() in OnLoad):

Console.WriteLine(GL.GetString(StringName.Vendor) + " | " + GL.GetString(StringName.Version) + " | " + GL.GetString(StringName.Renderer));

And copy/paste the results here? If running in Visual Studio, the result should be visible in the Output view. I would recommend putting a breakpoint on InitializeOpenGL as well. It should look something like this:

NVIDIA Corporation | 4.5.0 NVIDIA 382.53 | GeForce GTX 970/PCIe/SSE2

I would also recommend making sure that your graphics card (or integrated graphics) drivers are up-to-date.

Just solved this issue by upgrading to the newest OpenTK package (2.0.0).

I am using:
NVIDIA Corporation | 4.5.0 NVIDIA 378.49 | GeForce GTX 680/PCIe/SSE2

I am getting this
Microsoft Corporation | 1.1.0 | GDI Generic

I have updated openTK package to 2.0.0(Stable)
after that
Line 108 ::
OpenTK.Graphics.GraphicsContextException: 'Failed to make context 65536 current. Error: 6'

Do you still get the same string out from OpenTK 2.0.0? What graphics card do you actually have/is there actually an implementation besides the GDI Generic one? What OS are you running?

I would also try 3.0.0-pre, this is looking more like an OpenTK issue than a SharpNav issue right now

Microsoft Corporation | 1.1.0 | GDI Generic
this was when the OpenTK was 1.1(something )

after update to 2.0.0(Stable)(via Nuget Package Manager)
Edit This error still there even in 3.0.0-pre
OpenTK.Graphics.GraphicsContextException: 'Failed to make context 65536 current. Error: 6'
on line 108(ExampleWindow.cs)

I have
GTX 1080
Driver 382.53
Window 10 (latest version)

Ok it Solved
I Just deleted all the files in the SharpNav folder and re-extracted it
and Updated it to OpenTk 2.0.0(Stable)
now all working

Awesome! I'll bump up the nuget version to 2.0.0 in a bit and then close this issue.

before you close are there any place like discord or something where we can question about using it for new people like me

Closest thing would be a mailing list I set up a while ago, which hasn't really caught on: https://groups.google.com/forum/#!forum/sharpnav

I'm really stretched thin as far as how much time I have to maintain + develop SharpNav, but it's a port of Recast, so pretty much everything you read online about Recast can be applied to SharpNav.

Thanks