SOLVED: Windows 10 Update KB4057892 - ASCOM Components Unusable
Here at DC-3 Dreams, we have received a few reports of the Windows 10 Update KB40569892, the Cumulative Security Rollup for Jan 2018 rendering ACP unable to connect to devices, and inter-process connections between other components failing as well. We believe this is Microsoft's update for the recently discovered CPU hardware vulnerabilities called Spectre and Meltdown vulnerabilities. It just appeared a couple of days ago.
We have confirmed that this update does indeed prevent connections to ASCOM "local servers". This has far reaching implications. Fortunately, Microsoft did mention that there is a "known issue" with this update:
Symptom: When calling CoInitializeSecurity, the call will fail if passing RPC_C_IMP_LEVEL_NONE under certain conditions.
Workaround: Change the authentication level parameter to RPC_C_AUTHN_LEVEL_CALL
The usual level is indeed "none" since nothing in ASCOM etc. uses Distributed COM (DCOM) at all! Our ACP, as well as all of the ASCOM local servers (drivers for most devices nowadays, and the simulators) are affected. Since Windows 10 will repeatedly install this update if you uninstall it, only the Microsoft workaround will provide a short-term solution. I will work with the ASCOM developers to provide a long term solution if Microsoft doesn't promptly come out with another update that has the above "known issue" fixed the right way. Well they probably know how to do this already since they are smarter than I am with regard to COM etc.
The good news is that you can adjust the authentication level yourself. Rather than re-write all of the instructions, and relying on this semi-crude forum system to show pictures, I've written the instructions with pictures on our DC-3 Dreams Communication Center forum in the public section, where anyone can see it.
The Comm Center post just before this one has some analysis info. I'll do my best to monitor traffic here and help people identify things in the DCOMCNFG list of system IDs.
- I read the directions in the link again and changed everything to call.
I still had some problems that were again solved by turning on run as administrator for all ASCOM programs.