A few days ago, I freshly installed SQL Server 2019 Evaluation Edition using the media downloaded from the Microsoft's website, and subsequently noticed that a Windows service named "CNG Key Isolation" service was listed as a dependency, required for running our newly installed SQL Server instance:

Service Dependencies for our freshly installed SQL Server 2019 Evaluation Edition

Interestingly, I can not see the above to be a dependency for running prior versions of SQL Servers (certainly not for the versions of up to 2016), not even for the Enterprise Editions:

enter image description here

What does "CNG Key Isolation" service do for SQL Server 2019, that was not needed in 2016 or earlier versions? Note that being a dependency for SQL Server service means that SQL Server instance cannot be started up if this service is not running first - for example, if it is disabled. What makes this service so vital for running SQL Server 2019 and yet, not at all needed in previous versions?

PS: note that we do not have SQL Server 2017 anywhere in our environment so I could not check 2017. However, I was able to check versions 2016, 2014, 2012 as well as 2008 R2 and observe this service was NOT a dependency in these older versions.


  • I would guess it has to do with the fact you're running Evaluation Edition, but Microsoft would be able to best answer this.
    – J.D.
    Commented Sep 1, 2022 at 12:43
  • 1
    @J.D. Evaluation Edition is in use temporarily. We will upgrade to paid edition in couple of months. I will write an update once that is done.
    – RGO
    Commented Sep 2, 2022 at 0:16
  • I don't have any data as to why, but yes this is what happens. It's not related to being evaluation edition; upgrading a SQL instance from 2017 to 2019 will add this dependency as well. Commented Jul 14, 2023 at 7:18

1 Answer 1


CNG Key Isolation service will store a wireless network key or the required cryptographic information for a smart card.

  • Used by hackers black hat hackers
    – G Holland
    Commented Mar 10, 2023 at 19:03
  • 2
    Please edit your answer to add more information. And this only answers the what not the why. You could improve your answer by doing that and by citing a refetence. Commented Mar 10, 2023 at 20:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.