Important: Configuration Manager current branch version 1706 is needed for any ConfigMgr environment using WUfB deferral policies. ConfigMgr client version 1702 will periodically delete all WUfB deferral policies, if configured. This could lead to unintended results.
As you are probably aware, Windows 10 version 1607 introduced new Dual Scan behavior for enterprises that wanted Windows Update (WU) to be their primary update source while Windows Server Update Services (WSUS) provided all other content. In this scenario, the WU client automatically scans against both WSUS and WU, but it only accepts scan results for Windows content from WU. Stated another way, the Dual Scan enabled client ignores anything on WSUS from the “Windows” product family. If you configure a combination of Windows Update group policies (or their MDM equivalents, or the underlying registry keys corresponding to either set of policies), then Dual Scan will be automatically enabled. These policies are:
- Specify intranet Microsoft update service location (i.e. WSUS)
- Either of the “deferral” policies belonging to Windows Update for Business
- Select when Feature Updates are received
- Select when Quality Updates are received
To defer updates, many enterprise customers used the configuration above prior to 1607. For them, the new Dual Scan behavior was an unwelcomed change as it broke ConfigMgr software update deployments for any updates within the “Windows” product family. Demystifying “Dual Scan” provides details about Dual Scan as well as settings that enterprises can use to work around the new behavior.
The October cumulative update for 1703 includes new functionality and a new policy that allows Dual Scan to be disabled. The new policy, “Do not allow update deferral policies to cause scans against Windows Update”, when enabled, will disable Dual Scan. This allows enterprises that wish to configure deferral policies, the ability to do so without being concerned that Dual Scan will override administrator intent.
NOTE updated 10/19/2017: The Administrative Templates (.admx) for Windows 10 Fall Creators Update (1709) are required to configure the new policy, “Do not allow update deferral policies to cause scans against Windows Update”, at a domain level.
It is important to understand the expected behavior as it relates to ConfigMgr.
- Windows Update for Business deferral policy configured and deployed via ConfigMgr (Windows 10 version 1703 and higher) – If you configure and deploy WUfB deferral policy via ConfigMgr, Dual Scan will be automatically enabled*. That is, “Do not allow update deferral policies to cause scans against Windows Update” will be set to disabled on any ConfigMgr client where the WUfB deferral policy is deployed. Even if you enable “Do not allow update deferral policies to cause scans against Windows Update” at the domain level, that setting will be periodically overwritten by the ConfigMgr client. *Assumes that the “Specify intranet Microsoft update service location” policy is set to Enabled.
- Windows Update for Business deferral policy and Dual Scan disable policy configured and deployed via GPO – If you configure WUfB deferral policy as well as disable Dual Scan (e.g. enable the new policy) via GPO, those settings will be preserved by the ConfigMgr client.
- To use WUfB deferral policies while disabling Dual Scan, use GPO to configure all required settings.
- To use Dual Scan with WUfB deferral policies, configure and deploy WUfB policy via ConfigMgr.
- And if you’re still managing some Windows 10 version 1607 clients, the August cumulative update for 1607 also includes the new Dual Scan policy. You can use GPO to set deferral polices and disable Dual Scan when running ConfigMgr version 1706.