Windows 11 25H2 — Known Issues & Workarounds (Updated Oct 2, 2025)

Featured image illustrating the known issues and workarounds for Windows 11 25H2. On a blue background, a laptop with a warning icon is surrounded by four pictograms representing “DRM,” “shared folder (SMB),” “.msu installer,” and “USB + disc (installation media).” Flat, logo-free design.

Microsoft has begun the phased rollout of Windows 11 version 25H2 (the “2025 Update”), delivered as a small enablement package on top of 24H2. As with any major rollout, a few issues are already documented on the official Release Health dashboard. This post summarizes the current status and what you can safely do today.

目次

Quick summary

  • DRM playback glitches in some Blu-ray/DVD/Digital TV apps are partially resolved as of the September 29, 2025 preview update (KB5065789). Streaming services are not affected; some apps that use digital-audio DRM can still fail.
  • WUSA/.msu installs can fail with ERROR_BAD_PATHNAME when launched from a network share containing multiple .msu files. Mitigated via Known Issue Rollback (KIR); copying the file locally is an effective workaround.
  • SMBv1 shares may fail when NetBIOS over TCP/IP (NetBT) is involved after the September 2025 updates. Temporary workaround: allow TCP port 445 so connections use direct TCP; Microsoft has addressed the issue in KB5065789 for affected client builds. (Best practice: retire SMBv1.)
  • Media Creation Tool on Arm64: the tool won’t run as expected on Arm64 hosts (and it never creates Arm64 media). To create installation media, run the tool on an AMD64/x64 PC.

1) DRM-protected content fails to play in some apps

Symptoms. Certain Blu-ray/DVD/Digital TV applications can show copyright errors, freeze, stop unexpectedly, or display a black screen when playing protected content. Streaming services are not affected. Affected platforms include Windows 11 24H2 and 25H2.

Status. Partially resolved. Microsoft says scenarios using Enhanced Video Renderer (EVR) with HDCP were fixed in the September 29, 2025 preview update (KB5065789) and later updates. Apps using digital-audio DRM might still have issues; a permanent fix is in progress.

What to do now. Install the latest cumulative update (KB5065789 or newer) and update the playback app. If issues persist, consult the app vendor until Microsoft ships a full fix.

2) WUSA/.msu installs fail with ERROR_BAD_PATHNAME

Symptoms. Installing updates via WUSA or double-clicking a .msu from a network share that contains multiple .msu files can fail with ERROR_BAD_PATHNAME. After a restart, Settings may briefly keep showing “restart required.”

Workarounds and mitigation.

  • Copy the .msu locally and install from there (or ensure only one .msu exists in the share).
  • After installing and restarting, wait 15+ minutes—the Status page should refresh correctly.
  • Microsoft has applied KIR for many non-managed devices; IT admins can use the special Group Policy to enforce the rollback on managed fleets. A permanent fix is planned in a future update.
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3) SMBv1 connectivity issues after September updates

Symptoms. After installing updates on or after September 9, 2025, connecting to SMBv1 shares over NetBIOS over TCP/IP (NetBT) can fail (client or server side). Microsoft explicitly notes SMBv1 is deprecated; SMBv2/3 are not affected.

Workaround (short term). Allow TCP port 445 so Windows switches to direct TCP instead of NetBT; connections should resume. Microsoft has said a resolution is coming in future updates and has documented the workaround in support KBs. Additionally, client-side fixes are included in later updates (including KB5065789 for affected Windows 11 builds). Security best practice is to retire SMBv1 entirely.

4) Media Creation Tool does not run on Arm64 hosts

Symptoms. The Windows 11 Media Creation Tool (v26100.6584, released September 29, 2025) may show “We’re not sure what happened…” on Arm64 devices. The tool does not support creating Arm64 media; normally Arm64 devices can create x64 media, but that scenario currently fails.

Workaround. Use an AMD64/x64 PC to run the Media Creation Tool and create installation media. Microsoft is investigating.

Rollout notes for IT admins

  • WSUS/Configuration Manager availability. Windows 11 version 25H2 becomes available via WSUS/ConfigMgr on October 14, 2025 (coinciding with the October security release). Until then, it’s available via Autopatch/M365 admin center, the Software Download site, and Visual Studio subscriptions. Plan pilots accordingly.
  • Servicing model. 25H2 shares the 24H2 code base and is deployed as an enablement package; both versions receive monthly updates in the same servicing branch.

Recommended deployment approach

  1. Stage the rollout (pilot → broad) and confirm application/driver compatibility in a test ring.
  2. Apply the latest cumulative update (KB5065789 or newer) before or immediately after enabling 25H2 to pick up mitigations/fixes noted above.
  3. Eliminate SMBv1 where possible; if you must keep it temporarily, ensure TCP/445 is permitted while you migrate to SMBv2/3.
  4. For media creation on Arm64 devices, use an x64 host until Microsoft provides a fix.

Closing

Most early issues are mitigated or have clear workarounds. Check Windows Release Health periodically and keep devices on the latest cumulative update while you complete your 25H2 rollout.

Related Articles

・Windows 11 25H2 — Known Issues & Workarounds (Updated Oct 2, 2025)

・Windows 11 Version 25H2 Confirmed — Separating Facts from “Windows 12” Rumors

・Windows 11 25H2 for IT: WSUS Timeline, Pilot Plan, and the Enablement Package Model

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