Difference Between Content of Windows 10 SAC-T and SAC ISO Media

I was wondering whether there is any difference in the content of Windows 10 ISO files which released in two phases. There are two different ISO files released as part of Windows 10 SAC-T and SAC channels. More details about Semi-Annual Channel here. In this post, we will see what the differences between Windows 10 SAC-T and SAC ISO Media are.

Two Related posts on Windows 10 Servicing Topic:-

Windows 10 1709 Semi Annual CBB Ready for Broad Deployment and details about the release date of Windows 10 1709 CBB version media
Release management strategy of Windows 10 Servicing - Real World Experience

Content of this post:-

Windows 10 Patching - Avoid Fragmentation
ISOs Released part of SAC-T and SAC have Same Content?
Difference Between Windows 10 SAC-T and SAC ISO Media content?

Windows 10 Patching – Avoid Fragmentation

With Windows 10, patching made simpler with one cumulative monthly update that supersedes the previous month’s update, containing both security and non-security fixes. Another fact pointed out by Microsoft was most of the production Windows 7 and eight machines don’t have same patch level. The cause of the fragmentation of patches is because of a mix of individual updates as explained in the following diagram.

What is the big deal with fragmentation of patches in systems? As per Microsoft, Fragmentation where different PCs could have a different set of updates installed leading to multiple potential problems.

I recommend to avoid FRAGMENTATION of patches on Windows 10 machines from starting itself. So, I wanted to have all the Windows 10 computers in my network to have same patch level. Hence I had a valid question about different Windows 10 ISOs released as part of SAC-T and SAC channels. More details about Windows patch fragmentation.

Windows 10 SAC-T and SAC ISO Medias

ISOs Released part of SAC-T and SAC have Same Content?

No, the content of both ISOs is different. Windows 10 Semi-Annual Channel (Targeted) (e.g., released on 17th OCT 2017) ISO and Windows 10 Semi-Annual Channel ISO (e.g., will be published on 22nd Jan 2018) have different content. Windows 10 SAC-T and SAC ISO media are different.

In a scenario:- If I deploy 30% Windows 10 devices with SAC-T channel ISO and 70% Windows 10 devices with SAC channel ISO. Does this have a chance of fragmentation of patches on Win 10 systems? I hope, it won’t create fragmented systems because of cumulative nature of Windows 10 patches.

Update (18th Jan 2018) – I have had a Twitter discussion with Cristopher Alaya‏ on patch fragmentation topic. And as per him, the fragmentation would be still there. “There are updates deployed by Microsoft Update which are not included in the Cumulative Update, like the Servicing Stack update here: https://support.microsoft.com/en-us/help/4058702/servicing-stack-update-for-windows-10-version-1709 … It’s not in the CU.”

So, ideally, you are safe to start the development of Windows 10 core image for SCCM immediately after SAC-T ISO availability. More details available in my previous post “Release MGMT strategy for Windows 10 Semi-Annual Channel and SAC-T releases“.

But to avoid fragmentation of patches in systems, you need to inject patches released between SAC-T and SAC releases into your latest Windows 10 image. Another way to prevent fragmentation of patches is to keep all your Windows 10 systems up to date with the latest patch(s).

Windows 10 SAC-T and SAC ISO Medias

Difference Between Windows 10 SAC-T and SAC ISO Media content?

In the above section, we found that Windows 10 SAC-T and SAC ISO Media are different. In this article, we will get more details about the details of this difference. I was trying to find out an answer to the above question. I didn’t find a clear-cut answer on TechNet documentation.

I think, Microsoft deliberately uses the word “Refreshed media” to refer the Windows 10 SAC ISO. As SCCM admin, I don’t believe both REFRESH and UPDATE are same in this scenario as well.

I assumed and Michael confirmed through Twitter that “We do refresh the media for convenience, adding in a later cumulative update“. He gives a perfect example to make me understand the difference between the Windows 10 SAC-T and SAC ISO Media content. “So it’s the same BASE BUILD (e.g., 16299) but a later PATCH LEVEL (e.g., 16299.15 vs. 16299.125)“.

Windows 10 SAC-T and SAC ISO Medias


Windows 10 BASE Version is same for both Semi-Annual Channel (Targeted) and Semi-Annual Channel.

For example:-

Windows 10 1709 SAC-T Base version is 10.0.16299
Windows 10 1709 SAC Base version is 10.0.16299
Windows 10 1703 SAC-T Base version is 10.0.15063
Windows 10 1703 SAC Base version is 10.0.15063

The difference between Windows 10 SAC-T and SAC ISO Media is PATCH LEVEL. Windows 10 cumulative Patches are the only difference between the Windows 10 ISOs released as part of CB and CBB cycle. You can check this out in the following examples.

Windows 10 1709 SAC-T PATCH LEVEL is 16299.15
Windows 10 1709 SAC PATCH LEVEL is 16299.192 (I'm not sure Windows 10 1709 SAC ISO patch level until 22nd Jan 2018)

So, you can start building or creating Windows 10 images within SCCM once CB or SAC-T version of Windows 10 is released. No need to wait for CBB version of Windows to get published.

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