BSOD 114 (ASSIGN_DRIVE_LETTERS_FAILED): causes and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: Windows failed while assigning drive letters or boot-volume names during startup.

Could be also:
Constant	Type	OS
ERROR_INVALID_TARGET_HANDLE	Win32 error	Windows
EALREADY	errno	Linux
ELOOP	errno	Windows

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SESSION5_INITIALIZATION_FAILED	CONFIG_LIST_FAILED

ASSIGN_DRIVE_LETTERS_FAILED

Drive-letter assignment failure for ASSIGN_DRIVE_LETTERS_FAILED

ASSIGN_DRIVE_LETTERS_FAILED is bug check code 0x00000072. This bug check points at early mount-manager, volume, or boot-device naming state. It can occur before user mode can repair mappings because the system must name required volumes during boot.

How to read it in a dump

The important evidence is volume arrival, mounted-device state, partition signatures, and storage stack status.
Do not diagnose it as an Explorer drive-letter display problem.
Compare with NO_BOOT_DEVICE or storage/file-system crashes if they occur on the same machine.

What to check

Check disk signatures, partition layout, mount-manager state, boot configuration, and storage filter drivers.
Inspect recent cloning, imaging, SAN, or virtual-disk changes.
Use recovery environment logs if the system cannot boot far enough to write a normal dump.

References

Dump evidence

Preserve the complete dump, the four bug-check parameters, the exact Windows build, loaded-module list, and the event timeline immediately before the stop. AllStat summarizes the condition as “this result”; that sentence identifies the failure class, while the parameters and stack determine which object, driver, processor, or subsystem instance was involved.

Analysis order

Run WinDbg !analyze -v, then inspect the documented meaning of each parameter instead of relying only on the probably-caused-by line.
find the earliest abnormal event: driver update, firmware change, device reset, storage error, verifier report, resource exhaustion, or application hang connected with assign / drive / letters.
keep third-party filter, security, storage, graphics, and virtualization drivers in the module inventory; removing evidence before dump analysis can obscure the responsible path.

Do not repeatedly reboot a machine affected by this result before collecting the dump and event logs. Recovery actions should follow the component identified by the stack and parameters, not merely the symbolic stop-code name.

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