Windows not detecting NVME Drive after disabling CSM in BIOS

Troubleshooting Windows Detection Issues with NVMe SSD After Disabling CSM in BIOS

Many users seeking to enhance system security or enable features like Secure Boot often modify BIOS settings, such as disabling Compatibility Support Module (CSM). While these adjustments can facilitate modern security protocols, they occasionally lead to unforeseen hardware recognition problems within Windows. One common scenario involves Windows failing to detect an NVMe SSD after disabling CSM in BIOS, impeding normal system operation and data access.

Understanding the Context

In the process of preparing for a gaming beta, such as Battlefield 6, a user may attempt to enable Secure Boot for enhanced platform security. Achieving this often requires disabling CSM to enable UEFI mode exclusively. However, this change can disrupt the existing storage configuration, especially if the drive’s partitioning scheme or boot configuration isn’t aligned with UEFI boot standards.

Case Summary

The user reported that after disabling CSM and rebooting, Windows no longer recognizes the M.2 NVMe SSD unless CSM is re-enabled. Although the drive is already formatted with a GPT partition scheme—necessary for UEFI boot mode—Windows still fails to detect the drive once CSM is turned off. Such issues can be perplexing, especially when straightforward solutions seem insufficient.

Potential Causes and Solutions

1. Partition Style Verification

2. Confirm that the NVMe drive is partitioned with GPT. You can verify this in Disk Management or by running diskpart:
   diskpart
list disk
   The “GPT” column indicates the partition style for each disk. If your disk is not GPT, convert it, but ensure data backup beforehand.

3. UEFI Boot Mode Configuration

4. Ensure that the BIOS is set to UEFI mode exclusively and that Secure Boot is enabled.

5. Verify that the NVMe drive is set as the primary boot device.

6. Drive and BIOS Compatibility

7. Not all NVMe drives are fully compatible or may require specific BIOS updates.

8. Check for BIOS firmware updates that enhance NVMe compatibility.

9. Windows Boot Configuration

10. Disabling CSM can influence the boot configuration data (BCD). Confirm that Windows is set up for UEFI boot.

11. Use Windows recovery media to access Startup Repair or Command Prompt and run:
    bcdboot C:\Windows /l en-us /s S: /f UEFI
    Replace C:\Windows with your