Microsoft wants OEMs to build proper USB Type-C notification support in Windows 11

We already know that Windows 11 has robust support for USB Type-C connectivity problems, such as faulty connections, slow charging, unsupported accessories, and more. However, these notifications can only work if developers implement proper support for them too. Microsoft is now encouraging OEMs to be conscious of utilizing the built-in notification system in Windows 11 for better reliability and user experience.

USB Type-C ports may fail to show notifications due to several manufacturing problems from the OEM's side while building the PC. For example, Windows uses ACPI descriptors to identify USB Type-C ports and their functionalities, so if this markup is absent for a port, notifications will not work. Similarly, if a Type-C port has been accidentally mislabeled as Type-A, the user will experience the wrong alerts or other unexpected behavior. In the same vein, if a physically accessible and visible port has been marked as "internal", notifications will be suppressed too.

In order to work around these problems, Microsoft has recommended OEMs to audit ACPI descriptors for all USB ports, validate the notification behavior across supported configurations, coordinate with Microsoft's Windows Hardware Compatibility Program (WHCP) to ensure that new platforms meet testing requirements, and thoroughly document any exceptions to normal or expected behavior. Compatibility can be ensured through the Windows Hardware Lab Kit (HLK), the implementation of the _UPC (USB Port Capabilities) and _PLD (Physical Location of Device) ACPI descriptors, and testing under various diverse scenarios and configurations.

Microsoft has acknowledged that some OEMs may even want to disable data transfer over USB Type-C connections in untrusted environments. They should ensure that any such policies only apply to external ports and do not interface with other critical components like the touchpad and the keyboard. Redmond has even encouraged offering user-facing toggles for data transfer disablement to customers. You can find out more details in the blog post here.

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Posted Saturday 30 August 2025 at 5:49 pm AEST (my time).

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