Registry hack fixes WD SN770, SN580 Windows 11 24H2 blue screens (BSOD)

Microsoft's newest OS feature update, Windows 11 version 24H2 has some undocumented bugs and issues with several of them being related to disks. For example, users have expressed annoyance that they have not been able to delete 8.63 GB of data after upgrading their OS. Another problem is that the Windows SFC scan feature has been broken, although Microsoft has confirmed that the issue is being resolved with the upcoming KB5044384 update.

Following those, we now have users who are reporting problems on a specific brand of hardware, mainly Western Digital NVMe SSDs, wherein their drives are blue screen crashing after updating to Windows 11 24H2.

The issue seems to be happening on WD_Black SN770 and WD Blue SN580, both of which are DRAM-less and rely on the system memory for caching via host memory buffer (HMB). Users have been able to pinpoint that the problem is occurring as a result of incorrect host memory buffer size allocation and tweaking around this issue using the Registry Editor seems to fix it.

For those who may not be familiar, many SSDs come with a dedicated DRAM chip that acts as a buffer for metadata between the controller and the NAND flash memory. The presence of this DRAM cache improves write caching and generally reduces random access times. Those NVME SSDs that do not have the DRAM cache typically support the HMB technology which helps the controller access system memory via Direct Memory Access (DMA).

NVMe SSDs generally tend to allocate around 64 MB of this amount on Windows but they can also allocate around 100 MB or higher. This is where the problem seems to stem from as affected users have noticed that their HMB allocation is going up to 200 MB on the SN770 and SN580, thus causing a potential conflict of sorts which is eventually leading to blue screens of death (BSOD).

Unfortunately, it can be hard to figure out the HMB allocation amount on Windows without using certain third-party utilities like VLO's hmb-nvme app.

Regardless, there is a workaround for this using the good old Registry Editor wherein altering the DWORD value inside the "HmbAllocationPolicy" key in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorPort key fixes it by setting the allocation amount to 64 MB. To do this:

1. Open the Registry Editor app by running REGEDIT
2. Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorPort key
3. Create a new HmbAllocationPolicy subkey if it is already not present
4. Set the DWORD value of the above key to 0 or 2 (where 0 => HMB allocation off and 2 => HMB allocation is 64 MB)
5. Restart the PC

If your issue is resolved after doing the above, it is likely that the problem was a result of HMB allocation. Those on non-WD SSDs who are experiencing a similar issue can also try out the Registry tweak above until a Windows update or a drive firmware update fixes it once and for all.

You can also go to Feedback Hub and upvote the issue so it helps Microsoft become aware of the problem.

Source: WD forum