Windows 11 24H2 HMB Issues: NVMe SSDs, BSODs, and Firmware Fixes

Windows 11’s recent update cycle has once again exposed how fragile the hardware–software handshake can be: multiple user reports and vendor advisories show that changes in Windows 11’s Host Memory Buffer (HMB) negotiation and related storage behavior in version 24H2 triggered system instability on a narrow set of NVMe SSDs during sustained, large file transfers—manifesting most commonly as repeated Blue Screens of Death (BSODs) and hangs. [url="]Western Digital releases fix for Windows 11 24H2 BSODs — users are strongly advised to update their SSD firmware[/url])

Background​

Microsoft shipped Windows 11 24H2 as a major feature update that included a number of kernel- and storage-related improvements. Soon after the rollout, community threads, vendor support posts, and independent outlets began documenting a consistent pattern: on some systems, large sequential I/O—such as copying multi-gigabyte archives, virtual machine images, or raw video files—would trigger systroblem was reproducible in many reports and clustered around DRAM‑less NVMe SSDs that rely on the NVMe Host Memory Buffer (HMB) feature. This is not a generic “Windows update slowed transfers” story. The observable failure mode was instability under sustained I/O—kernel crashes, system hangs, and BSOD loops—rather than minor performae vendors and Microsoft coordinated responses: WD and SanDisk published firmware updates for specific SKUs, and Microsoft placed compatibility holds to prevent the 24H2 rollout on machines with affected firmware until corrected firmware was applied.

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What is HMB and why it matters for large transfers​

HMB explained, simply​

Host Memory Buffer (HMB) is an NVMe feature that allows DRAM‑less SSDs to use a slice of system RAM as a caching buffer for metadata and translation tables. HMB bridges the performance gap between DRAM‑equipped SSDs and cheaper DRAM‑less designs by giving the SSD temporary access to host memory without adding onboard DRAM. For many DRAM‑less drives, HMB materially improves sequential and random transfer performance during sustained workloads.
Historically, operating systems and drives negotiated modesr example ~64 MB), which kept HMB usage predictable and within the firmware developers’ tested envelope. In Windows 11 24H2, that negotiation behavior changed in ways that increased HMB allocations in some cases—reports indicate the OS could allow near‑200 MB allocations in scenarios where legacy builds would not. That larger allocation appears to be the proximate trigger in the incidents described here.

Why large file transfers expose the problem​

Large sequential transfers stress the storage stack for extended periods: sustained writes/read operations, large metadata churn, and frequent lookups of the drive’s mapping tables. On DRAM‑less controllers that depend on HMB, increased HMB allocation can cesource patterns the SSD’s firmware expects. If the firmware is not tolerant of the larger host‑backed buffer or contains edge‑case bugs tied to HMB size, the drive may behave unpredictably under load—causing controller errors that bubble up as kernel faults in the host OS. In practice, users observed BSODs or the OS reporting storNVMe/controller errorsransfers.

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Timeline: reports, vendor responses, and Microsoft actions​

1. October 2024 — As Windows 11 24H2 began broader distribution, early community reports noted instability with certain Western Digital and SanDisk NVMe SKUs. Discussions on vendor forums and tech sites surfaced consistent crash reports tied to large transfers and HMB-related errors.
2. Late October–November 2024 — Western Digital and SanDisk investigated and released firmware updates for identified SKUs (notably specific 2TB variants of WD_BLACK SN770, SN770M, WD Blue SN580, WD Blue SN5000, and the SanDisk Extreme M.2 2TB). Independent outlets advised users to update firmware and to back up data before proceeding.
3. After vendor fixes — Microsoft used its compatibility hold mechanism to block the 24H2 update for systeware until users applied firmware updates; Microsoft’s community and Q&A pages referenced the holds and advised updating SSD firmware per vendor guidance.
4. Ongoing — Community-sourced registry workarounds and rollback guidance circulated as stopgaps for systems rendered unusable by BSOD loops.

This coordinated pattern—community detection, vendor firmware updates, and Microsoft compatibility holds—shows a textbook supply‑chain defense: isolate the vulnerable configurations, reduce exposure, and distribute firmware fixes to affected units.

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Which SSDs and systems were affected (scope and caveats)​

Vendor advisories explicitly targeted a narrow set of SKUs, primarily high‑capacity (notably 2TB) variants of WD and SanDisk NVMe drives. That list included, but was not necessarily limited to:

• WD_BLACK SN770 (specific 2TB SKUs)
• WD_BLACK SN770M (selected SKUs)
• WD Blue SN580 (2TB models)
• WD Blue SN5000 (spsk Extreme M.2 NVMe (2TB SKU)

Always confirm the exact model and SKU printed on your drive and check the vendor’s firmware advisory before taking action. Firmware advisories are often SKU‑specific and sometimes apply only to certain firmware ranges.
Important caveat: early community posts included dramatic claims of “bricked” drives and data loss. Those claims were frequently anecdotal and not always corroborated by vendor diagnostics or independent lab reproductions. While drives did become inaccessible or unstable in some scenarios, controller vendors performing controllewidespread, permanent drive destruction attributable solely to the Windows update was not reproducible at scale. Treat extreme claims cautiously until validated—firmware diagnosis and vendor support logs are the definitive sources.

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Symptoms and diagnostics: what users reported​

• Repeated BSODs (common errors included kernel crashes tied to storNVMe/controller faults and the “Critical Process Died” message).
• System hangs or unresponsiveness mid‑copy during large file transfers (multi‑GB files or lengthy sequential writes).
• In some cases, fresh installs of Windows 11 24H2 failed or the installer blocked due to compatibility holds referencing SSD firmware checks.
• Event Viewer logs freqe or controller error messages that pointed to I/O/firmware faults.

If you encounter stability only when performing sustained transfers (e.g., copying a VM image, a raw camera archive, or large compressed archives), that pattern strongly suggests an I/O stress fault consistent with HMB/firmware interplay rather than a random system error.
dance: steps for end users and IT managers

Immediate safety checklist (ranked by safety)​

• 1. Back up first. Before any firmware change, registry tweak, or roll‑back, copy critical data to another physical device or verified cloud backup. Firmware updates can fail and occasionally cause data loss if interrupted.
• 1. Check your drive model and firmware. Use vendor tools (e.g., Western Digital Dashboard) or Device Manager details to confirm model, SKU, and current firmware version. Only rely on official vendor firmware utilities—not third‑party firmware tools.
• 1. Apply vendor firmware updates if your SKU is listed. Follow the vendor’s step‑by‑step instructions and ensure your machine has stable power (laptop: plug in AC power). Expect a required reboot antime.
• 1. If you cannot update firmware or your system is in a BSOD loop: consider rolling back to the prior Windows build (23H2) or booting into Safe Mode to perform repairs. Reverting often restored stability while firmware remediation propagated.
• 1. Registry workaround (last resort, for experienced users only): Set HMB allocation policy to limit or disws registry. This mitigates crashes by removing the HMB negotiation pressure but will reduce performance on DRAM‑less drives. Documented registry keys and values varied by post; follow only vetted guidance and back up the registry.

Step‑by‑step: updating Western Digital / SanDisk firmware (safe checklist)​

1. Backup the SSD data to another physical device.
2. Download and install the official vendor tool (Western Digital Dashboard / SanDisk utility).
3. Use the tool’s firmware update function and follow the prompts precisely.
4. Do not interrupt the update; ensure power stability.
5. Reboot when instructed and validate system stability under typical workloads, including a large file transfer test if practical.

Vendors warned that firmware updates can rarely cause data loss if interrupted—hence the emphasis on backups.

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Registry workaround: mechanics, benefits, and trade-offs​

Several community posts and troubleshooting guides circulated a registry-based mitigation that forcibly limits or disables HMB allocation on affected systems. Typical steps included creating or editing a DWORD value such as HMBAllocationPolicy under StorPort/stornvme parameter keys and setting it to values that either disable HMB (value 0) or force a conservative allocation (value 2 for ~64 MB). This prevented the larger HMB negotiation that triggered firmware issues in some drives and restored stability in many cases.

• Benefit: Quick way to stop BSOD loops caused by HMB negotiation without performing a firmware update or OS rollback.
• Trade-off: Disabling HMB reduces performance on DRAM‑less SSDs—sequential and random performancey under heavy workloads.
• Risk: Registry edits are inherently risky; incorrect changes can destabilize the system. Back up the registry and follow exact steps from trusted documentation.

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Risk analysis and larger context​

Strengths of the response​

• Coordinated vendor reaction: Western Digital and SanDisk produced firmware fixes in a reasonable timeframe for affected SKUs. Those firmware updates resolved many reported cases when applied correctly.
• Microsoft’s compatibility holds: Blocking 24H2 on systems with vulnerable firmware reduced exposure and prevented more users from immediately encountering the bug during the update process. Microsoft also published guidance and allowed vendor remediatWorkarounds and rollbacks provided practical escape hatches for users in the field who needed immediate stability fixes.

Remaining risks and uncertainties​

• Firmware update risk: While firmware solved many cases, applying firmware carries a non‑zero risk. Vendors explicitly advise backing up before proceeding due to the small chance of a failed update rendering a drive unusable.
• Fragmented initial communication: Early information was distributed across forums, tech media, and vendor posts rather than a single, detailed technical advisory. That made the situachnical users to evaluate and increased the circulation of shaky anecdotes.
• Anecdotes vs. reproducible failures: Claims of widespread permanent drive damage circulated, but controller vendors conducting lab tests did not reproduce mass bricking tied solely to the Windows update. Independent verification remained essential to differentiate isolated failures (due to interrupted firmware updates, failing hardware, or unique OEM integrations) from reproducible, systemic defects. Users should insist on vendor diagnostics before assuming physical damage.

Related but distinct incidents: exercise caution with attribution​

Separate incidents in the Windows update ecosystem (for example, security patches that were later implicated in disappearing‑drive reports in mid‑2025) demonstrate this pattern: storage issues sometimes appear after specific updates, but the root cause can vary—faulty controller firmware, corner‑case OS behavior, or interaction effects unique to certain workloads. As such, don’t assume all SSD incidents after a Windows update share a single root cause; always seek vendor confirmation for your exact model and firmware.

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Recommendations for power usild update windows and validation tests: Before pushing major Windows feature updates to broad fleets, test them under representative heavy‑I/O workloads (large file transfers, VM migrations, database operations). This reduces the chance of a surprise failure mode in production.​

• Maintain a firmware inventory: Track SSD models, SKUs, and firmware versions across assets. This allows targeted blocking or staged remediation when suppliers release fixes.
• Use vendor tools for firmware updates: Avoid third‑party utilities for firmware application; vendors provide tested update mechanisms and explicit SKU guidance. Back up before changing firmware.
• Communicate clearly to end users: When an update is blocked by compatibility holds, provide concise instructions (how to check the device model, how to update firmware safely, and where to obtain official tools). Clear instructions reduce risky DIY attempts.
• For critical transfers, validate beforehand: If you must move large datasets (VM images, archive snapshots) immediately after a feature update, validate the target system’s firmware and, if possible, perform a short stress‑test copy to catch instability early.

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Conclusion​

The Windows 11 24H2 HMB incident demonstrates how low‑level OS changes can reveal latent firmware fragilities in specific hardware SKUs—especially when workloads exploit the very features (like HMB) designed to boost performance under high I/O. The chain of detection, vendor firmware updates, and Microsoft’s compatibility holds largely contained the issue, but the episode underlines several consistent lessons: always back up before firmware or OS upgrades, prefer vendor‑provided firmware utilities, and treat dramatic community claims with caution until vendor diagnostics confirm them.
For users planning large, critical transfers, practical steps remain simple and essential: confirm your SSD’s model and firmware, apply vendor firmware updates if you’re listed as affected (after backing up), and postpone heavy I/O until your configuration is validated. If you face immediate instability, the registry workaround and OS rollback provide emergency relief, but those are temporary measures with trade‑offs and should be used only with full awareness of the risks.
The episode is both a technical cautionary tale and a test of ecosystem resilience: coordinated vendor patches and Microsoft’s rollout controls worked as intended to reduce widespread harm. At the same time, it exposes the fragility of complex interactions between OS-level optimizations and third‑party firmware, and it reinforces the need for transparent, centralized advisories when issues touch critical infrastructure such as storage.

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Appendix: Quick checklist (for immediate action)

1. Back up important data now.
2. Check your SSD model and firmware via vendor tool or Device Manager.
3. If listed as affected, update firmware using the vendor’s official utility and guidance.
4. If firmware isn’t available and you’re experiencing crashes, consider rolling back to Windows 11 23H2 or apply the registry HMB workaround as a last resort.
5. Contact vendor support for diagnostics if problems persist; don’t assume permanent hardware damage without vendor confirmation.

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Source: MSN https://www.msn.com/en-us/news/tech...vertelemetry=1&renderwebcomponents=1&wcseo=1]