I think the reason it is crashing straight away now is that SharpCap is now in 'live view' mode, so will try to take an exposure immediately rather than waiting for you to press the capture button. It's still failing on the same action - trying to start an exposure of 1s duration, which ought not be failing really
You might be able to bypass this by getting the camera into 'high speed' mode - that uses a different method to start exposures that might just work. I think this procedure ought to allow that to happen
1) Put SharpCap back into 'still mode' by pressing the 'Live View' button under the file menu again
2) Open the camera, but do not capture any frames
3) Change the 'High Speed Mode' control on the right to 'On'
4) Put SharpCap into 'live video mode' again using the Live View button
That might just get you images from the live view mode of the camera. It might also be interesting to change the exposure before trying capturing in still mode - I can't see why a 1s exposure would be a problem, but who knows.
Unfortunately the only Atik camera I have to test with is an old CCD 314L+ model, which seems to work OK. It also doesn't have the same feature set as the Horizon 2, so I cannot try out these tricks myself.
cheers,
Robin