After rolling out Windows 11 25H2, also known as Windows 11 2025 Update, Microsoft has confirmed that the Media Creation Tool has stopped working on devices with Arm64 CPUs.

The Windows 11 Media Creation Tool is a free utility that helps users download the latest version of Windows and create bootable installation media for clean installs, system recovery, or upgrading to a new device.

On affected systems, the company states that users are seeing "We're not sure what happened, but we're unable to run this tool on your PC." error messages.

"The Windows 11 media creation tool (version 26100.6584), released on September 29, 2025, might not work as expected on devices with Arm64," Microsoft said in a Tuesday support document.

"The media creation tool doesn't support creating media for use on Arm64 devices. However, Arm64 devices are normally able to create media for x64 devices—this functionality is not working as expected."

However, Microsoft added that this known issue is not expected to impact most users, since this feature is rarely used on Arm64 devices.

While investigating this bug and seeking a fix, Redmond has provided a temporary workaround for affected customers, which requires them to switch to an AMD64 PC if they wish to create Windows bootable installation media.

"To prevent this issue, the media creation tool can be used on devices that have AMD64 processors. Use of the tool on these devices is not affected," it added.

Microsoft has announced the general availability of Windows 11 25H2 on Tuesday, a minor update that shares the same platform release as Windows 11 24H2 and is installed through an enablement package (eKB).

Once installed, the Windows 11 2025 Update will activate multiple enhancements that have gradually rolled out over the past year, including Copilot enhancements, Windows Hello with a modernized interface, Copilot+ PC unique features like Recall (preview) and Click to Do, as well as various user interface, accessibility, input, and system management improvements.