Microsoft confirms caching issues in Windows 10 KB5034203 and newer updates

Microsoft has updated the official Windows documentation with details about a newly discovered bug in the recent Windows 10 updates. According to the company, some Windows 10 devices within enterprise networks might experience problems with using Microsoft Connected Cache nodes, resulting in an increase in download traffic from the public internet.

For context, Microsoft Connected Cache is a feature (currently in preview) that offers software-based caching to deliver "Microsoft content" across enterprise or education networks. Companies can use Microsoft Connected Cache to distribute Windows updates, Office Click-to-Run apps, Microsoft 365 App updates, client apps, and definition updates for Windows Defender. Internet service providers can also use MCC to reduce network bandwidth usage for Microsoft products.

Microsoft says the Connected Cache feature is for companies who want to "move towards modern management and away from Configuration Manager Distribution points."

The discovered bug in Windows 10 affects systems with versions 21H2 and 22H2 with KB5034203 (the January 2024 non-security update) or later. It is most likely to hit computers with DHCP Option 235, causing them to download updates and apps from outside their companies' networks.

The problem does not affect home users since Microsoft Connected Cache is a feature made specifically for internet service providers and enterprise and education environments (some home users are currently dealing with other sorts of issues).

Microsoft is working on resolving the problem with Microsoft Connected Cache nodes in Windows 10, and a fix should arrive in one of the upcoming updates. Meanwhile, IT admins can mitigate the problem using one of the following two options:

• Option 1: Configure Microsoft Connected Cache endpoint in DOCacheHost policy as indicated in Cache hostname. Additionally, DOCacheHostSource has to be set to 1 or removed as indicated in Cache hostname source. Note that by default, the DOCacheHost and DOCacheHostSource policies have no value.
• Option 2: This issue can also be mitigated using Group Policies available through our support channel. Organizations can request help through Support for business.

You can find more information about Microsoft Connected Cache in the official documentation.

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