Windows 11 24H2 causes a blue screen with some SSDs — how to fix it in the registry

Windows update 11 24H2 contains some undocumented errors. Users have reported conflicts with certain Western Digital NVMe SSDs.

The «blue screen of death» appears to be occurring with the WD Black SN770 and WD Blue SN580, both of which have no DRAM cache and rely on system memory for caching via the host memory buffer (HMB). Users have been able to pinpoint the issue to be a result of a misallocation of the memory buffer size — it can be adjusted in the Windows registry.

Many SSDs now have built-in DRAM memory, which acts as a buffer for data between the controller and the NAND flash memory to speed up file operations. SSDs that don’t have a DRAM cache usually support HMB technology, which helps the controller access system memory directly (DMA).

SSDs typically use 64 MB of system memory, but can get 100 MB or more. This seems to be where the conflict that leads to the BSOD occurs: victims have noticed that the amount of memory for HMB is as high as 200 MB with SN770 and SN580 drives.

There is a workaround using a registry editor. Change the DWORD value of the HmbAllocationPolicy key in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorPort section, where you need to set the memory size to 64 MB. To do this, you need:

1. Open the REGEDIT program
2. Go to the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorPort
3. Create a new HmbAllocationPolicy subsection if it does not already exist
4. Set the DWORD value for this key to 0 or 2 (where 0 => HMB allocation is disabled, and 2 => 64 MB)
5. Restart your PC

Users of SSDs from other manufacturers can also try these registry settings until a Windows update or firmware update fixes the issue. The issue is being discussed on the WD forum, and there are no official solutions yet.

Source: NeoWin