Looks like a common problem with short exposures. Make sure you’re using a USB3 cable (throughput is important on these cameras). I didn’t read the entire thread, there might be other solutions.
I just installed the new ASCOM 6.2 platform and found out there is also a new ASCOM driver on the ZWO site (click the ASCOM tab on the http://astronomy-imaging-camera.com/software/ page, installed version v1.0.2.16), That seemed to fix the issue… I’m sooo happy now! Works like a charm!!!
I just noticed the latest ASCOM driver causes problems with the fan. It switches off after some time (fan fysically stops but in software it indicates 100% and temperature goes up to + some degrees Celsius (instead of minus 25C). I stepped back one ASCOM version to v1.0.2.13 and I hope it will be better this time…
ZWO can be a little flaky on their drivers. On the plus side, they’re really responsive! Go check out their forums and post, I bet they’ll have it fixed super quick.
Post some pictures when you get it working all the way. Those are neat cameras.
There’s was a v1.0.2.15 driver as well, not sure where that one went. The .13 was an improvement over the prior releases, but I still got a blank frame now and again with the .13. I’ve gone to the .15 and things seem to be stable. I haven’t tried the .16, but will take your word for the fan issue as they’d placed a Fan Off option for the first time in the .15 version.
The bad part is they’ve removed the .txt file with the changes off their site so you could see what they were before downloading.