What is

Unknown status / error value


Could be also:



The USER_MODE_HEALTH_MONITOR_LIVEDUMP bug check has a value of 0x000001C9. It indicates that one or more critical user mode components failed to satisfy a health check.


This topic is for programmers. If you are a customer who has received a blue screen error code while using your computer, see Troubleshoot blue screen errors.


Parameter Description
1 Process that failed to satisfy a health check within the configured timeout.
2 Health monitoring timeout (seconds).
3 Watchdog source. In combination with process address this helps to identify the source. See below for possible values. These values are shared with USER_MODE_HEALTH_MONITOR.
4 Reserved.

Watchdog Source Values

0  : WatchdogSourceDefault
     Source was not specified
1  : WatchdogSourceRhsCleanup
     Monitors that RHS process goes away when
     terminating on graceful exit
2  : WatchdogSourceRhsResourceDeadlockBugcheckNow
     RHS was asked to immediately bugcheck machine
      on resource deadlock
3  : WatchdogSourceRhsExceptionFromResource
      Resource has leaked unhandled exception from an entry point,
      RHS is terminating and this watchdog monitors that
      process will go away
4  : WatchdogSourceRhsUnhandledException
      Unhandled exception in RHS.
      RHS is terminating and this watchdog monitors that
      process will go away
5  : WatchdogSourceRhsResourceDeadlock
      Monitors that RHS process goes away when
      terminating on resource deadlock
6  : WatchdogSourceRhsResourceTypeDeadlock
      Monitors that RHS process goes away when
      terminating on resource type deadlock
7  : WatchdogSourceClussvcUnhandledException
      Unhandled exception in clussvc.
      clussvc is terminating and this watchdog monitors that
      process will go away
8  : WatchdogSourceClussvcBugcheckMessageRecieved
      Another cluster node has sent message asking to bugcheck this node.
9  : WatchdogSourceClussvcWatchdogBugcheck
      User mode watchdog has expired and created netft watchdog
      to bugchecked the node.
       0xA : WatchdogSourceClussvcIsAlive
      Cluster service sends heartbeat to netft every 500 millseconds.
      By default, netft expects at least 1 heartbeat per second.
      If this watchdog was triggered that means clussvc is not getting
      CPU to send heartbeats.
      0x65 : WatchdogSourceRhsResourceDeadlockPhysicalDisk
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0x66 : WatchdogSourceRhsResourceDeadlockStoragePool
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0x67 : WatchdogSourceRhsResourceDeadlockFileServer
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0x68 : WatchdogSourceRhsResourceDeadlockSODAFileServer
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0x69 : WatchdogSourceRhsResourceDeadlockStorageReplica
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0x6A : WatchdogSourceRhsResourceDeadlockStorageQOS
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0x6B : WatchdogSourceRhsResourceDeadlockStorageNFSV2
       A subclass of WatchdogSourceRhsResourceDeadlock.
      0xC9 : WatchdogSourceRhsResourceTypeDeadlockPhysicalDisk
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.
      0xCA : WatchdogSourceRhsResourceTypeDeadlockStoragePool
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.
      0xCB : WatchdogSourceRhsResourceTypeDeadlockFileServer
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.
      0xCC : WatchdogSourceRhsResourceTypeDeadlockSODAFileServer
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.
      0xCD : WatchdogSourceRhsResourceTypeDeadlockStorageReplica
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.
      0xCE : WatchdogSourceRhsResourceTypeDeadlockStorageQOS
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.
      0xCF : WatchdogSourceRhsResourceTypeDeadlockStorageNFSV2
       A subclass of WatchdogSourceRhsResourceTypeDeadlock.


One or more critical user mode components failed to satisfy a health check.

Hardware mechanisms such as watchdog timers can detect that basic kernel services are not executing. However, resource starvation issues, including memory leaks, lock contention, and scheduling priority misconfiguration, may block critical user mode components without blocking DPCs or draining the nonpaged pool.

Kernel components can extend watchdog timer functionality to user mode by periodically monitoring critical applications. This livedump indicates that a user mode health check failed in a manner such that we will attempt to terminate this application and will keep monitoring if termination completes in time. If termination does not complete in time, then the machine will be bugchecked It restores critical services by rebooting and/or allowing application failover to other servers.

(This code can never be used for a real bugcheck; it is used to identify live dumps.)

See Also

Troubleshooting a Failover Cluster using Windows Error Reporting

Failover Clustering system log events


Bug Check Code Reference

About “What is” service

Many of users are faced with the problem of interpreting errors that occur during the work of operating systems. In some cases, the operating system reports that an error has occurred and displays only an integer error code value. Often it is difficult to even roughly understand the cause of the error from the information given out. Our “what is” service contains a database of errors in Windows, Linux, Macos and Solaris operating systems. The database contains tens of thousands of values. In most cases, the online service will be able to help with the definition of the short name of the error and its detailed description.


Current version of service supports following types of error and status codes:

NTSTATUSMany kernel-mode standard driver routines and driver support routines use the NTSTATUS type for return values. Additionally, drivers provide an NTSTATUS-typed value in an IRP’s IO_STATUS_BLOCK structure when completing IRPs. The NTSTATUS type is defined in Ntdef.h, and system-supplied status codes are defined in Ntstatus.h.
Win32 errorWin32 error codes MUST be in the range 0x0000 to 0xFFFF, although Win32 error codes can be used both in 16-bit fields (such as within the HRESULT type specified in section 2.1) as well as 32-bit fields. Most values also have a default message defined, which can be used to map the value to a human-readable text message; when this is done, the Win32 error code is also known as a message identifier.
HRESULTHRESULT is a data type used in Windows operating systems, and the earlier IBM/Microsoft OS/2 operating system, to represent error conditions, and warning conditions.
The original purpose of HRESULTs was to formally lay out ranges of error codes for both public and Microsoft internal use in order to prevent collisions between error codes in different subsystems of the OS/2 operating system.
HRESULTs are numerical error codes. Various bits within an HRESULT encode information about the nature of the error code, and where it came from.
HRESULT error codes are most commonly encountered in COM programming, where they form the basis for a standardized COM error handling convention.
HTTP Status CodeHypertext Transfer Protocol (HTTP) response status codes. Status codes are issued by a server in response to a client’s request made to the server. It includes codes from IETF Request for Comments (RFCs), other specifications, and some additional codes used in some common applications of the HTTP. The first digit of the status code specifies one of five standard classes of responses. The message phrases shown are typical, but any human-readable alternative may be provided.
errnoInteger value, which is returned by system calls and some library functions in the event of an error to indicate what went wrong. errno is defined by the ISO C standard to be a modifiable lvalue of type int, and must not be explicitly declared; errno may be a macro. errno is thread-local; setting it in one thread does not affect its value in any other thread.
Kern ReturnApple Kernel return codes.
Ipp StatusThe IppStatus constant enumerates the status values returned by the Intel IPP functions, indicating
whether the operation is error-free.
Types of error and status codes

Source code

The service is based on the open source library AllStat. Its sources are available on our git server. We will be grateful for your participation in the finalization of the library and ideas for the development of the service. You can also download ErrorLookup libraries and utilities from our site.