Windows Error Codes
Searchable reference for Windows error codes — system errors, BSOD stop codes, NTSTATUS, WMI, RPC, MSI installer, AD/Kerberos, BitLocker, DNS, VPN, Hyper-V, COM/DCOM and more. Each entry includes the hex/decimal value, severity, root causes, and a step-by-step troubleshooting workflow.
How to read a Windows error code
Windows surfaces error codes through Win32, NTSTATUS, HRESULT, and many subsystem-specific spaces. Each code has a hex form (e.g. 0x80070005), a signed decimal form (-2147024891), and a symbolic name (ERROR_ACCESS_DENIED). This page lets you look up any of those forms, see what triggers the code, and follow a vetted troubleshooting workflow tuned for the originating subsystem (Windows Update, BSOD, AD/Kerberos, BitLocker, etc.).
44 codes
0x8000FFFFCriticalE_UNEXPECTED
Unexpected COM failure — catastrophic error.
0x8009030FCriticalSEC_E_MESSAGE_ALTERED
The message or signature supplied for verification has been altered.
0x80090327CriticalSEC_E_DOWNGRADE_DETECTED
The system detected a possible attempt to compromise security. Kerberos downgrade attack detected.
0x80092013CriticalCRYPT_E_REVOKED
The certificate is revoked. Check CRL or OCSP connectivity.
0x80310026CriticalFVE_E_CONV_READ_ERROR
BitLocker encountered an error reading the drive during conversion. The drive may be failing.
0x80310038CriticalFVE_E_NO_RECOVERY_KEY_FOUND
No BitLocker recovery key found. Check Active Directory or Azure AD for escrowed key.
0xC0000005CriticalSTATUS_ACCESS_VIOLATION
Memory access violation. A process attempted to access memory it has no rights to. Often causes application crashes.
0xC0000185CriticalSTATUS_IO_DEVICE_ERROR
The request could not be performed because of an I/O device error. Often a failing disk.
0xC0000257CriticalSTATUS_DOWNGRADE_DETECTED
A downgrade attack has been detected. Kerberos security failure.
0xC004F025CriticalSL_E_NOT_GENUINE
The software is not genuine. License validation failed.
0xC1900101CriticalMOSETUP_E_DRIVER_FAILURE
Feature update failed due to a driver issue. Common during Windows 10/11 upgrades. Update or remove problematic drivers.
0xC1900200CriticalMOSETUP_E_COMPAT_SYSREQ_BLOCK
System does not meet minimum requirements for the Windows upgrade.
0xC1900208CriticalMOSETUP_E_COMPAT_INSTALLREQ_BLOCK
An incompatible app is blocking the Windows upgrade. Uninstall flagged apps and retry.
0x0000000ACriticalIRQL_NOT_LESS_OR_EQUAL
Kernel accessed memory at improper IRQL. Almost always a faulty driver.
0x0000001ACriticalMEMORY_MANAGEMENT
Serious memory management error. Run MemTest86 to check RAM.
0x0000001ECriticalKMODE_EXCEPTION_NOT_HANDLED
Kernel mode exception was not handled. Check minidump for offending driver.
0x00000023CriticalFAT_FILE_SYSTEM
Problem in the FAT file system. Run CHKDSK.
0x00000024CriticalNTFS_FILE_SYSTEM
Problem with the NTFS file system driver. Run CHKDSK on the affected volume.
0x0000002ECriticalDATA_BUS_ERROR
Parity error in system memory. Usually indicates faulty RAM or motherboard.
0x0000003BCriticalSYSTEM_SERVICE_EXCEPTION
A system service threw an exception. Often caused by a faulty driver. Check minidump for offending module.
0x00000044CriticalMULTIPLE_IRP_COMPLETE_REQUESTS
A driver attempted to complete an IRP more than once.
0x00000050CriticalPAGE_FAULT_IN_NONPAGED_AREA
Invalid memory referenced. Caused by faulty RAM, drivers, or system files.
0x00000051CriticalREGISTRY_ERROR
Error related to the registry. May indicate disk failure or corrupted hive.
0x0000005ACriticalCRITICAL_SERVICE_FAILED
A critical service failed to start during boot.
0x00000069CriticalIO1_INITIALIZATION_FAILED
I/O initialization failed during boot.
0x00000074CriticalBAD_SYSTEM_CONFIG_INFO
Registry or BCD store is corrupt. Run Startup Repair or restore from backup.
0x0000007ACriticalKERNEL_DATA_INPAGE_ERROR
Required page of kernel data could not be read into memory. Often a failing disk or bad RAM.
0x0000007ECriticalSYSTEM_THREAD_EXCEPTION_NOT_HANDLED
A system thread generated an exception the error handler did not catch. Usually a driver issue.
0x0000007FCriticalUNEXPECTED_KERNEL_MODE_TRAP
The CPU generated a trap the kernel did not catch. Often hardware failure or overclocking issue.
0x00000080CriticalNMI_HARDWARE_FAILURE
Non-maskable interrupt from hardware. Indicates serious hardware failure.
Page 1 of 2
Next →