
Microsoft confirmed that its September 2025 cumulative update for Windows 11, identified as KB5065426 (and preceded by the August preview KB5064081), introduced a regression that breaks playback of certain HDCP- and DRM‑protected video streams in legacy playback apps — notably those that use the Enhanced Video Renderer (EVR) with HDCP enforcement or platform DRM for digital audio — and that a targeted fix has been staged through the Release Preview channel while a broader rollout is prepared.
Background
The problem traces to two servicing packages released in late summer 2025. Microsoft published the optional August preview update KB5064081 on August 29, 2025, and the September cumulative update KB5065426 on September 9, 2025. Within days of the September rollup rolling out, users and OEM / media‑software vendors began reporting playback failures when attempting to use digital‑TV tuner software, Blu‑ray and DVD player applications, and some broadcast capture tools that rely on legacy pipelines. By mid‑September the issue had been acknowledged via Microsoft’s support and Release Health channels and documented across multiple trade and community outlets. On September 17, 2025 Microsoft staged a targeted remediation to the Release Preview channel (KB5065789) aimed at restoring protected playback for affected apps while broader distribution work continued.This is not a streaming / CDN outage. The regression is specific to protected playback pipelines that depend on the operating system’s protected rendering path — the coordinated handoff between the media framework, drivers and the GPU that ensures decrypted frames are never deposited into ordinary process memory. Modern streaming services that use their own app‑level DRM and rendering paths (for example, UWP/WinUI Media Foundation clients or browser‑based Widevine/PlayReady flows) reported no interruption.
What exactly is breaking — symptoms and scope
Symptoms seen by users
- Copyright or content protection errors reported by playback applications immediately after attempting to start a title.
- Playback that starts but is repeatedly interrupted with "protection" or device output errors.
- Black screens (audio only) or frozen video frames while audio continues.
- Complete failure to render video with no obvious error dialog in some apps.
- Some reports of failure only when external displays or capture devices were attached; others reported failures on internal panels.
Which applications and hardware are affected
- Third‑party Blu‑ray/DVD players that still use DirectShow / EVR pipelines.
- Digital TV / broadcast tuner applications and capture/recording software built on older DirectShow or Media Foundation EVR sinks with HDCP enforcement.
- Some capture device workflows that require a secure path (for example, protected tuner cards or set‑top capture devices).
What is not affected
- Most mainstream streaming services and app‑managed DRM flows (Netflix, Disney+, and similar) that use modern Media Foundation or browser‑based DRM were reported to be unaffected.
- Content that is not DRM or HDCP protected continues to play normally.
Technical explanation: EVR, protected rendering, HDCP and DRM
To understand why a cumulative OS update can block playback, it helps to unpack the components involved.Enhanced Video Renderer (EVR)
- EVR is a legacy Windows component used by DirectShow and some Media Foundation paths to render video frames to the screen. It was designed to create a secure, composited Direct3D surface for video presentation and to cooperate with Windows’ protected media pipeline.
- Microsoft documents EVR as a legacy renderer that has been largely superseded by the Simple Video Renderer (SVR) and newer Media Foundation APIs, but many existing players and broadcast/capture applications still rely on EVR for compatibility with DirectShow filters and older plug‑ins.
Protected rendering path and DRM
- When content is protected by DRM (PlayReady, Widevine, AACS for Blu‑ray, etc.), the media framework and the GPU drivers establish a trusted rendering path so decrypted frames are presented only to secure Direct3D surfaces. This prevents the decrypted pixels from being copied into ordinary system memory or captured by software.
- If any link in that chain — the application API, the OS media framework, drivers, or the monitor/display output negotiation — indicates an inconsistency, the playback framework fails closed to avoid exposing protected content.
HDCP
- High‑bandwidth Digital Content Protection (HDCP) is a link‑level protocol enforced over HDMI/DisplayPort (and historically DVI). It performs a cryptographic handshake between the source (PC/GPU) and sink (monitor/TV) and, when negotiated successfully, permits secure transmission of high‑value content.
- HDCP is distinct from DRM but complementary: DRM controls license/usage rules, while HDCP enforces output restrictions to external sinks.
Why an OS patch can stop playback
- The Windows media stack, drivers and GPU firmware negotiate a secure chain for protected content. Changes to any of these control points — including what Microsoft ships in a cumulative update — can alter timing, handshake semantics, or interface expectations.
- The August and September servicing updates changed behavior that the EVR + HDCP + platform DRM chain expected, causing third‑party players that rely on the legacy path to detect an integrity problem and block rendering.
Microsoft’s response and remediation timeline
- August 29, 2025 — Microsoft released the optional preview update KB5064081 (identified as the earlier event that introduced the regression).
- September 9, 2025 — Microsoft released the cumulative update KB5065426 (OS Build 26100.6584) to broad audiences via Patch Tuesday. Community reports of DRM/HDCP playback failures amplified after this rollup carried forward the prior change.
- Mid‑September 2025 — Microsoft acknowledged the issue via its support channels and Windows Release Health messaging, confirming that some Digital TV and Blu‑ray/DVD applications might experience playback failures after installing KB5064081 or later updates.
- September 17, 2025 — Microsoft began staging a targeted remediation to the Release Preview channel (builds distributed as KB5065789 / builds 26100.6718 / 26200.6718). The Release Preview notes explicitly stated the update "addresses an issue that affects playback of protected content in certain Blu‑ray, DVD, and digital TV apps" — indicating a surgical fix targeted at the regression.
- Microsoft’s public guidance at the time advised impacted users to monitor Windows Update for hotfixes and to delay installation of the affected updates if protected playback was critical to their environment.
Practical mitigation: what affected users can do now
If you rely on physical media playback or tuner software and saw problems after the August/September updates, here are practical, tiered steps to mitigate while awaiting an official wide release:- Confirm the timing
- Check whether playback problems began immediately after installing an update dated August 29 or September 9, 2025 (KB5064081 or KB5065426). If so, the correlation is strong.
- Check Microsoft’s update channels
- Look for a Release Preview or hotfix entry in Windows Update; Microsoft staged KB5065789 to Release Preview on or about September 17, 2025. If you participate in Insider Release Preview and your device is eligible, that build will contain the targeted fix.
- Short‑term rollback (desktop / power‑users)
- Create a full system restore point or a disk image before taking action.
- Uninstall the problematic LCU using the Windows Update uninstall or DISM / Remove‑Package methods, or via the wusa command (for example: wusa /uninstall /kb:5065426). Note that if the combined package includes an updated servicing stack update (SSU), a simple wusa uninstall may not always fully remove all components; follow Microsoft guidance and, if needed, consult the "remove the LCU" instructions in the KB article.
- After rollback, reboot and verify playback. If problems persist, consider an earlier system restore point.
- Driver rollback
- If you updated GPU drivers around the same time, try a driver rollback to the prior stable version. Some playback paths are sensitive to GPU driver + OS combinations. Reinstall the manufacturer driver from the vendor’s site (NVIDIA/AMD/Intel) if rollbacks fail.
- Application updates / alternate players
- Check whether your Blu‑ray or tuner application vendor has issued an update or specific guidance. Many vendors publish compatibility notes or patched builds for scenarios like this.
- If the application supports multiple renderers, configure it to use a modern Media Foundation path or Simple Video Renderer (SVR) if available, but be aware that not all legacy players expose that option.
- Avoid risky moves on production machines
- Don’t join the Release Preview on production or production‑adjacent media centers without testing; Release Preview builds may contain other pre‑release changes. If you choose to test KB5065789 on a representative machine, verify playback thoroughly first.
- When in doubt, wait for the official push
- If playback is not critical right now, delaying the affected OS updates until Microsoft confirms the fix in the general release channel is the safest path.
Who should care the most — impact analysis
- Media‑center enthusiasts, home theater PC (HTPC) users, and people using hardware capture/tuner devices are the primary affected group. Their workflows frequently depend on EVR and DirectShow compatibility.
- Corporate kiosks, digital signage, and broadcast test systems that use specialized capture hardware could be disrupted if playback is part of the core function.
- The average consumer who watches streaming content via browser or native apps is unlikely to notice an effect because those apps use modern DRM paths that were not implicated.
Why this happened: architecture and risk considerations
- EVR remains present in Windows for compatibility. It acts as a bridge between older DirectShow capture/renderer filters and the Media Foundation world. Legacy software often assumes subtle behavioral specifics of that bridge.
- Cumulative updates change shared OS components. When the media stack, audio/DRM subsystem, or driver expectations shift, third‑party components and filter chains that were coded against older behavior can fail to negotiate a secure path.
- The protected pipeline is intentionally defensive: when a handshake or capability check fails, players fail closed to prevent content leakage. That protective posture is by design but means regression impact is abrupt and highly visible for use cases that must remain functional.
- Pilot cumulative updates in representative environments that include legacy hardware and specialized media workflows.
- Maintain rollback and disaster recovery plans for critical kiosks or systems reliant on legacy rendering stacks.
- Monitor vendor advisories for drivers and third‑party playback apps when new OS servicing waves are rolled out.
Strengths and weaknesses of Microsoft’s handling
Notable strengths
- Microsoft publicly acknowledged the regression and documented the behavior in its support/Release Health channels rather than leaving users to rely solely on community troubleshooting.
- The decision to stage a surgical fix in the Release Preview channel (KB5065789) reflects a conservative remediation strategy: validate the targeted fix with Insiders before broad distribution.
- Microsoft continued to emphasize that mainstream streaming DRM paths were not affected, which helped reduce unnecessary alarm for a majority of users.
Potential weaknesses and risks
- The regression made its way from an August optional preview into the September cumulative rollup, demonstrating how optional preview builds can still influence mainstream updates and create surprise regressions.
- Users who do not follow community or Microsoft Release Health channels may not know to delay the update if they rely on affected apps.
- The remediation approach relies on users either enrolling in Release Preview or waiting for the broader rollout — both of which create a window of vulnerability for impacted workflows.
- Uninstalling cumulative updates is not trivial for non‑technical users; providing a clear, officially documented rollback procedure (including SSU interactions) is essential and was not as visible in the early hours of the incident.
Longer‑term considerations for media apps and IT teams
- Vendors that still ship DirectShow/EVR‑based players should prioritize migrating to Media Foundation with the Simple Video Renderer (SVR) or newer APIs exposed by MediaPlayer/IMFMediaEngine. Microsoft has explicitly recommended new code use MediaPlayer/IMFMediaEngine rather than EVR.
- IT teams that manage kiosks, digital signage, or HTPC fleets should:
- Maintain a pilot ring and test cumulative updates on a sample of devices that reflect production hardware and software stacks.
- Keep documented rollback and restoration processes that include steps for removing LCUs and handling SSU side effects.
- Communicate update windows proactively to downstream teams that manage specialized hardware.
Takeaway and conclusion
This incident is a classic example of how modern operating systems must simultaneously advance security and preserve compatibility. The Windows 11 August preview (KB5064081) introduced a compatibility regression that carried into the September cumulative update (KB5065426) and caused protected playback failures in legacy EVR‑based applications. Microsoft acknowledged the issue and staged a focused remediation via Release Preview (KB5065789) to restore the protected playback path for affected apps.For most users — those who stream video through mainstream apps — there is no impact. For a narrower but technically important set of users who depend on Blu‑ray/DVD players, broadcast tuners, or legacy capture pipelines, the regression was immediately disruptive and required careful mitigation: rollbacks, driver checks, or validated deployment of Microsoft’s staged fix.
The broader lessons are straightforward: organizations and power users that depend on specialized hardware or legacy media stacks must treat OS servicing as a change that requires testing, and software vendors must continue moving away from legacy renderers toward modern, actively maintained media APIs. Until Microsoft completes the broader rollout of the fix, affected users should back up systems, consider the cautious uninstall options described above, and monitor Windows Update and vendor advisories for the official remediation.
Source: TechPowerUp Windows 11 24H2 September Patch Breaks HDCP/DRM Video Playback