Microsoft has quietly begun rolling out an optional Windows 11 preview update — KB5074105 — that bundles user-facing features, quality fixes, and a long-awaited change to Smart App Control, while also expanding the system’s Cross‑Device Resume (Android → Windows) capabilities. This package is an optional preview of next month’s cumulative release and is notable because it both restores certain usability controls that many power users have long asked for and introduces continuity features that could matter to people who move workflows between Android phones and Windows PCs.
Background
Microsoft publishes preview (optional) updates ahead of the monthly Patch Tuesday to let users and IT teams test changes before they become mandatory. KB5074105 was posted at the end of January 2026 as a Release Preview package for both Windows 11 24H2 and 25H2, updating target builds to
26100.7705 and
26200.7705 respectively. The update mixes staged feature rollouts — which Microsoft enables server‑side over time — with broad quality fixes that apply immediately after installation. That hybrid approach means installing the KB makes you eligible for the new experiences, but it does not guarantee instant access to everything because Microsoft continues to use controlled feature rollout (CFR) gating.
Why this matters now
- It’s optional: You must opt in through Windows Update’s “Optional updates available” UI to get KB5074105 before it becomes a mandatory Patch Tuesday package. That gives testers and cautious users control over uptake.
- It contains both feature expansions (Cross‑Device Resume, MIDI modernization) and usability/security changes (Smart App Control toggle, Windows Hello ESS peripheral fingerprint support), so the update will be relevant to a broad set of users — creators, security‑conscious consumers, and enterprise administrators.
What’s inside KB5074105: feature highlights and fixes
KB5074105 is not a small patch. The release notes and independent coverage highlight a combination of feature expansion and bug fixes that address a raft of complaints and incremental feature requests.
- Cross‑Device Resume (expanded) — Microsoft extends the handoff-style resume functionality to more Android scenarios. The update advertises the ability to continue activities from an Android phone on a Windows PC — examples call out Spotify playback, continuing Microsoft 365 edits started in the Copilot mobile app, and resuming browsing sessions from supported Android browsers. This operates as a metadata-based “AppContext” handoff to the desktop handler, which prefers native desktop apps when available and otherwise falls back to the browser.
- Smart App Control (SAC) lifecycle change — Perhaps the most socially visible change: SAC can now be toggled on or off from Windows Security without requiring a clean reinstall of Windows. Previously, turning SAC off was effectively permanent for that Windows installation; re-enabling required a complete OS reset or reinstall. The change significantly reduces the friction of using SAC for users who occasionally need to run unsigned tools or install developer utilities that SAC might block.
- Windows MIDI Services modernization — The update modernizes MIDI handling, adding improved support for MIDI 1.0 and MIDI 2.0 scenarios, shared ports across applications, and a developer SDK for MIDI services. This is aimed squarely at music creators and app developers.
- Windows Hello ESS peripheral fingerprint support — Enhanced Sign-in Security (ESS) now supports external fingerprint readers, which helps desktop setups that don’t include built‑in sensors. This broadens biometric support for more Windows 11 systems.
- Accessibility and input refinements — Improvements to Narrator, Voice Access, and Voice Typing (including a new wait time option) aim to make voice and screen‑reader interactions more practical.
- Usability and reliability fixes — The update bundles many smaller fixes: Start Menu behavior corrections, a fix for the missing password icon at login, enhancements to File Explorer reliability (especially for network and remote paths), lock screen and desktop icon behavior improvements, and other system crash mitigations reported across consumer threads.
Deep dive: Smart App Control finally becomes manageable
What changed — and why it matters
Smart App Control was designed as a strict, proactive execution‑control layer that stops unknown or suspicious binaries from launching by relying on Microsoft’s app intelligence. The problem: once a device’s installation decided to
not enforce SAC, there was historically no supported way to re-enable it other than a complete OS reset. That made SAC impractical for developers, power users, and creators whose workflows rely on frequent installs of unsigned tools. KB5074105 removes that permanence: a new toggle under
Windows Security > App & Browser Control > Smart App Control settings lets you switch SAC on and off at will.
Practical impact for users and admins
- For home users: This change turns SAC from a once‑decided, high‑friction security posture into a manageable protection layer. If a legitimate app is blocked, you can temporarily disable SAC, complete the install, and re-enable SAC without wiping the device. That is a meaningful usability win.
- For IT teams and enterprises: The toggle introduces a governance vector. If SAC is centrally relevant to endpoint protection, administrators must ensure policy and management controls prevent unauthorized disabling. Group Policy, Intune, and other endpoint management tools will be the place to enforce SAC state in managed fleets; KB5074105 simply makes the client‑side toggle available again. Microsoft’s notes and rollout behavior indicate this is a staged change and may be subject to enterprise controls.
Security trade-offs and caveats
- Turning SAC off reduces one layer of defense: it still leaves SmartScreen and Defender running, but removing SAC widens the attack surface if the operator is not careful. Users should avoid leaving SAC disabled permanently unless they have alternative, commensurate protections in place. Enterprise policy should treat this toggle as a privileged configuration.
- SAC is still not a per‑app allowlist. The toggle solves the permanence problem but does not yet provide granular per‑app exceptions; that remains a feature request for some power users. Microsoft has not yet documented an official per‑app whitelist workflow in the KB. If that’s a requirement for your environment, plan accordingly and test the new SAC behavior before relying on it.
Cross‑Device Resume: how it works, and why it’s more than a gimmick
The technical approach
The expanded Cross‑Device Resume mechanism uses a lightweight metadata payload — an AppContext — that the phone supplies to the PC’s resume handler. When the PC receives the AppContext, Windows decides whether to open the corresponding activity in a native desktop app (when available) or in the default browser as a fallback. This model lets developers opt into the experience and allows Microsoft to present a consistent “resume” prompt on the Windows taskbar. The update explicitly targets online and cloud‑reachable activities; offline‑only phone‑local files are not part of the supported scenarios.
Real‑world examples called out by Microsoft
- Spotify: resume playback started on your Android phone directly in the desktop Spotify client.
- Microsoft 365 files: continue editing documents started in Microsoft’s Copilot mobile app; if the desktop Office app is present the file opens natively there.
- Supported browsers: some Android browser sessions (Microsoft cited Vivo Browser in its examples) can be resumed on the PC.
Practical limitations and privacy considerations
- Controlled rollout: Microsoft is gatekeeping the feature, so even after installing KB5074105 you may not see all resume scenarios until Microsoft enables the server‑side entitlement for your account, device, or OEM partner. That’s typical for continuity features that involve third‑party apps on phones.
- Cloud dependence: Resume works only for cloud‑reachable or web‑accessible activities. If your workflow involves files stored locally only on the phone, Cross‑Device Resume will not hand that data to the PC. That preserves a surface‑area constraint but limits offline utility.
- Privacy and telemetry: handing off an AppContext between devices implies metadata exchange across Microsoft services and partnered apps. Users and administrators should expect telemetry and capability entitlements to be involved; check privacy controls and enterprise policies if sensitive data is in play. Microsoft’s release notes do not claim local-only handoff for offline-only content.
Reliability fixes and quality-of-life corrections
KB5074105 bundles numerous smaller but consequential fixes that target widely reported annoyances and stability regressions:
- Start Menu reliability and behavior fixes — resolves specific cases where the Start Menu would misbehave or fail to load expected entries.
- Login UX — fixes issues such as the password‑icon omission at the login screen that caused confusion in multi-account or PIN scenarios.
- File Explorer and network path responsiveness — improvements to how File Explorer handles remote hosts and network‑backed folders.
- System crash mitigations — a number of rare but high‑impact crash scenarios (some tied to prior January patches) are addressed in this preview, making the package a useful step for anyone who experienced regressions after earlier updates.
These fixes are the kinds of changes that make KB5074105 interesting to a broad audience: even if you don’t care about MIDI or Cross‑Device Resume, the cumulative quality improvements may be worth an early install for affected users.
How to get KB5074105 (and why you might wait)
KB5074105 is optional. Microsoft is making it available through Windows Update’s preview channel and also as offline .msu installers for users who prefer manual patching.
- Open Settings > Windows Update.
- Look for Optional updates available and find KB5074105.
- Select Download & Install to apply the preview build (you’ll be advanced to OS Build 26100.7705 or 26200.7705 depending on your release).
- If preferred, download the offline .msu installers (Microsoft has posted these to its catalog) and apply them manually — useful in controlled or air‑gapped environments.
Why you might wait
- Controlled feature rollout: installing the update does not guarantee immediate access to server‑gated features. If you’re not keen on preview bits, you can wait for the feature to arrive automatically through Microsoft’s normal rollout or for the next Patch Tuesday mandatory push.
- Known early adopter risks: community threads show mixed early experiences — some users installed cleanly, while others reported install failures, partial UI regressions, or peripheral oddities after applying the update. If you need a rock‑solid production machine, delay until the features are widely validated.
- Backup and test first: as with any optional preview, create a system restore point and image backup before applying KB5074105, especially on machines you rely on for work. The update is large and touches multiple components (boot, kernel, windowshell), so a rollback path is essential.
Early community signals: rollout, wins, and wrinkles
Independent coverage and forum threads indicate this release is being staged. Some community testers have already received the new SAC toggle and Cross‑Device Resume prompts, while others report the features are still server‑gated or absent despite installing the update. That is consistent with Microsoft’s use of gradual rollouts for new UI and cloud‑enabled features.
At the same time, Reddit and forum chatter has surfaced a range of install experiences:
- Reports of the update failing mid‑install and triggering repeated retries for some users.
- A minority of users reporting regressions such as Wi‑Fi or UI oddities after applying the preview; in several cases rolling back the preview resolved the symptom. Those reports are not universal, but they matter because they echo the pattern from earlier January servicing waves where some machines experienced higher‑impact regressions.
These community data points underline that while Microsoft has fixed many small problems in KB5074105, preview packages can behave differently across the enormous diversity of PC hardware and OEM drivers in the field.
Recommendations: who should install, and how to test safely
If you manage endpoints or you’re a power user who likes to test early features, KB5074105 is worth considering. Here’s a practical approach:
- Back up first. Create a full system image or at least a restore point before installing.
- Test on a non‑critical machine. Validate the SAC toggle workflow, Cross‑Device Resume with your Android phone and target apps, and your key productivity or creative apps. If you rely on specific audio/MIDI setups, test those too given the MIDI service changes.
- Validate device security posture. If your environment mandates strict application controls, ensure SAC policy and management tooling are configured and tested with the new toggle behavior. Intune and Group Policy can enforce settings where needed.
- Monitor typical problem vectors. After installing, watch the Start Menu, File Explorer behavior, and any network or driver‑related quirks; these were areas Microsoft specifically targeted with fixes.
For home users who
don’t need the features yet, waiting for the cumulative update that rolls the preview into the mandatory channel may be the lower‑risk path.
Risks, unknowns, and what Microsoft hasn’t fully answered
- Feature availability uncertainty — Controlled rollouts mean you may install the KB and still not see Cross‑Device Resume or the SAC toggle until Microsoft enables them for your account, OEM, or device. That can be confusing for users expecting an immediate change.
- No per‑app SAC allowlist yet — The toggle restores flexibility but does not replace the long‑requested capability to allow single apps while keeping SAC enforcement. The lack of a fine‑grained exception mechanism remains a usability gap for some advanced workflows.
- Potential regressions remain a possibility — Community reports show the usual spectrum of early adopter instability. While Microsoft has addressed several high‑impact bugs, the diversity of devices and drivers means you should expect heterogeneous experiences until the wider rollout completes.
- Privacy and telemetry tradeoffs with Cross‑Device Resume — AppContext handoff implies metadata exchange and server‑side entitlements. Microsoft’s release notes make it clear the experience relies on cloud reachability; enterprise privacy teams should evaluate the implications for regulated data.
Final analysis: a pragmatic, useful preview with sensible caveats
KB5074105 is a meaningful preview release. It corrects a persistent usability flaw in Smart App Control, expands a continuity feature that could become genuinely useful for Android + Windows users, and includes a set of stability and accessibility improvements that matter to daily usage. For users who have been frustrated by SAC’s permanence, the toggle is the headline change and a clear win. For creators and musicians, the MIDI modernization may deliver practical benefits.
That said, the update is a preview and carries the normal preview caveats: staged rollouts, potential for device‑specific regressions, and the need for administrators to reassess controls in managed environments. If you run critical workloads, test first. If you love new features and don’t mind troubleshooting, this preview is a legitimate early look at what Microsoft will push more broadly next month.
KB5074105 is now available for manual installation via Windows Update’s optional preview channel or as offline installers. If you opt in, proceed with backups, test the new SAC and Cross‑Device Resume flows with your real apps, and treat the release as a staged stepping stone rather than a final, broadly enforced platform change.
Source: PCWorld
Optional Windows 11 patch remedies several broken issues