Windows 11 KB5124010 preview: install now or wait for October?

Windows Update on a home PC just grew an optional preview again. On September 22, 2026, Microsoft published KB5124010, a non-security cumulative preview for Windows 11 24H2 and 25H2.

Builds after install:

25H2: 26200.9550
24H2: 26100.9550

This is not Patch Tuesday. It will not replace the next security rollup. It is the quality / features preview you opt into from Settings → Windows Update → Advanced options → Optional updates. If you only want mandatory security packages, you can ignore it and wait for October’s security update. If you like early fixes and small quality-of-life changes, read the highlights and decide.

For the September security baseline and the emergency USB-audio follow-up, see our September Patch Tuesday home guide and the out-of-band emergency update note.

What is worth knowing at home

Microsoft’s KB highlights several changes that show up on ordinary home machines (availability can be gradual):

File Explorer: Better handling of previews for files downloaded from the web (HTML gets a Preview anyway button; many non-HTML files such as PDFs preview automatically). Home section remembers expanded/collapsed state. Cloud thumbnail previews in Details are more reliable. An address-bar edit glitch is addressed.
Emoji 17.0: New emoji (Microsoft calls out examples such as distorted face, fight cloud, and hairy creature) via Windows + ., plus refreshed designs for some existing emoji.
Tips widget: Short Windows tips on the Widgets board or lock screen widgets.
Bluetooth: Reliability and audio fixes, including better volume flyout feedback for Classic Audio accessories, connection-state accuracy, Settings page stability, microphone compatibility, a crash while streaming Bluetooth audio, and LE Audio improvements.
Copilot key remap: A new setting to remap the Copilot key to Right Ctrl or the Context Menu key if you want familiar shortcuts back.
Accessibility / Magnifier / Settings / Touchpad: Quality improvements, including an Open apps maximized accessibility option and extra precision-touchpad scroll gestures.
Camera and File History: Normal-rollout fixes for a built-in camera that stopped working in some apps, and a File History “Reconnect your drive” false alarm when the backup drive was fine.

None of that is urgent the way a security update is urgent. It is “nice if you hit the bugs” territory.

Should a normal person install now?

Install the preview now if:

You are on 24H2 or 25H2, updates have been smooth for you lately, and you want File Explorer / Bluetooth / emoji fixes early.
You specifically want the Copilot key remap or Tips widget.
You are comfortable being a little earlier than the October security package.

Wait for October Patch Tuesday if:

Your PC is “finally stable, please do not poke it.”
You rely on USB speakers or headsets that might still be in Microsoft’s USB Audio Class 1.0 Code 10 / no audio known-issue bucket (see below).
You prefer one reboot cycle with the monthly security update rather than an optional preview plus another package later.

Optional previews are production-quality in Microsoft’s wording, but they are still optional. Skipping them is a valid home choice.

Notes that matter more than the emoji pack

Final preview for 24H2, and a hard date for Home/Pro

Microsoft says KB5124010 is the final non-security preview for Windows 11 version 24H2. Supported 24H2 editions still get monthly security updates for their servicing lifecycle, but preview seekers need a newer Windows 11 version for future non-security previews.

More important for many home PCs: Windows 11 version 24H2 Home and Pro reach end of updates on October 13, 2026. After that, those editions stop getting fixes for known issues, time zone updates, technical support, and monthly security / preview packages. If winver or Settings → System → About still says 24H2 on a Home or Pro PC, plan the upgrade path to a supported Windows 11 version before that date. Do not wait until the second week of October to discover you are out of security updates.

Secure Boot certificate refresh is ongoing

Secure Boot certificates used by most Windows devices started expiring in June 2026. Microsoft has been pushing newer certificates to consumer and non-managed devices through Windows Update and says devices without the new certs still start and still take ordinary updates. Let Windows Update keep running. You do not need a special home ritual beyond staying current.

USB Audio Class 1.0 Code 10: reason to skip for some people

Microsoft still documents a known issue after the September 8 security update: some USB Audio Class 1.0 devices may fail to start, show Device Manager Code 10, produce no audio, leave volume stuck at zero, or make Sound settings unresponsive. The KB5124010 page repeats that Microsoft is still working on a resolution.

If your USB speakers or headset are already weird after September’s security packages, skip this optional preview for now unless Microsoft later marks the audio issue fixed. Prefer waiting for a servicing note that clears it. If stereo works and you are not chasing optional features, waiting is fine.

Office-managed PCs only (brief)

Microsoft also documents a known issue where some domain-joined, Credential Guard / Machine Identity Isolation setups can lose domain trust after September 8 security updates and later packages. That is an office-managed PC problem. Home Microsoft accounts and typical home PCs are not the focus here. If your laptop is joined to a workplace domain, let whatever team manages that PC handle it.

How to install (or confirm you are skipping)

Open Settings → Windows Update.
Choose Advanced options → Optional updates.
If KB5124010 is listed, open it, select it, and install.
Restart when asked.
Confirm with Win + R → winver: look for 26200.9550 (25H2) or 26100.9550 (24H2).

If nothing optional appears, either the preview has not reached your PC yet, or Windows does not consider you eligible. Check again in a day or two, or wait for October’s security update.

Bottom line

KB5124010 is an optional non-security preview for Windows 11 24H2/25H2 (builds 26100.9550 / 26200.9550) with File Explorer, Bluetooth, Emoji 17, Copilot key remap, and Tips widget improvements. Install from Optional updates if you want those early; otherwise wait for October’s security package. If you use finicky USB Audio Class 1.0 gear, skip until Microsoft clears the Code 10 known issue. If you are still on 24H2 Home or Pro, treat October 13, 2026 as a real end-of-updates deadline and upgrade before then. That is the whole job.

Image: Windows-style bloom wallpaper marketing art (blogs.windows.com).