Microsoft’s latest operating system feature update, Windows 11 version 24H2, has introduced a series of undocumented bugs, particularly affecting disk-related functionalities. Users have reported frustrations over an inability to delete approximately 8.63 GB of data post-upgrade. Compounding these issues, the Windows System File Checker (SFC) scan feature is currently malfunctioning, although Microsoft has acknowledged the problem and is working on a resolution through the forthcoming KB5044384 update.
Specific Hardware Challenges
In addition to these general concerns, users with Western Digital NVMe SSDs are experiencing significant problems, notably blue screen crashes following the update to Windows 11 24H2. The affected models include the WD_Black SN770 and WD Blue SN580, both of which are designed without dedicated DRAM. Instead, they utilize host memory for caching through a technology known as Host Memory Buffer (HMB).
The root of the issue appears to be linked to incorrect allocation of the host memory buffer size. Users have discovered that the HMB allocation for these drives is unexpectedly increasing to 200 MB, whereas typical allocations range from 64 MB to 100 MB. This discrepancy seems to create conflicts, ultimately leading to the dreaded blue screens of death (BSOD).
For those unfamiliar with the intricacies of SSD technology, many SSDs are equipped with a dedicated DRAM chip that serves as a buffer for metadata between the controller and NAND flash memory. This DRAM cache enhances write caching and reduces random access times. However, NVMe SSDs lacking this DRAM typically rely on HMB technology to facilitate access to system memory via Direct Memory Access (DMA).
While determining the HMB allocation on Windows can be challenging without third-party utilities, there is a viable workaround using the Registry Editor. By adjusting the DWORD value within the “HmbAllocationPolicy” key in the HKEYLOCALMACHINESYSTEMCurrentControlSetControlStorPort path, users can set the allocation back to 64 MB. Here’s how to implement this fix:
- Open the Registry Editor app by running REGEDIT.
- Navigate to the HKEYLOCALMACHINESYSTEMCurrentControlSetControlStorPort key.
- Create a new HmbAllocationPolicy subkey if it is not already present.
- Set the DWORD value of the above key to either 0 (to turn off HMB allocation) or 2 (to set HMB allocation at 64 MB).
- Restart your PC.
Should this adjustment resolve the issue, it likely indicates that the HMB allocation was indeed the culprit. Users with SSDs from other manufacturers experiencing similar difficulties may also benefit from this Registry tweak until a more permanent solution is provided through a Windows update or firmware revision.
To further assist in addressing these issues, users are encouraged to visit the Feedback Hub and upvote the reported problems, thereby helping Microsoft prioritize necessary fixes.
