List of Windows XP Services and Descriptions

This article lists the standard services provided with Windows XP. Not all of these services may be installed on a given system, depending on the optional software and hardware installed. The first line in each table row contains the service name in boldface, followed by the service's display name. Where DLL files are listed, the service is run from svchost.exe. These details are discussed in more detail later in the section.

Services with a Start mode of "Auto" are started when Windows boots, but may shut themselves down if they have no work to do. Services with a Start mode of "Manual" are usually started automatically by other services or applications when they are needed.

The list of Windows XP services includes:

• 6to4 IPv6 Helper Service. Provides DDNS name registration and automatic IPv6 connectivity over an IPv4 network. (Installed with the IPV6 optional network protocol. The Tcpip6 item listed in the dependency list is a network protocol driver, not a service.)

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	6to4svc.dll
  Dependencies:	RpcSs, Tcpip6, winmgmt

  
  
• Alerter Notifies selected users and computers of administrative alerts.

  Start mode:	Auto
  Login account:	LocalService
  DLL file:	alrsvc.dll
  Dependencies:	lanmanworkstation

  
  
• ALG Application Layer Gateway Service. Provides support for third-party protocol plug-ins for Internet Connection Sharing and the Windows Firewall.

  Start mode:	Manual
  Login account:	LocalService
  EXE file:	alg.exe

  
  
• AppMgmt Application Management. Provides software installation services such as Assign, Publish, and Remove.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	appmgmts.dll

  
  
• aspnet_state ASP.NET State Service. Provides support for out-of-process session states for ASP.NET.

  Start mode:	Manual
  Login account:	NetworkService
  EXE file:	aspnet_state.exe

  
  
• AudioSrv Windows Audio. Manages audio devices for Windows-based programs.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	audiosrv.dll
  Load group:	AudioGroup
  Dependencies:	PlugPlay, RpcSs

  
  
• BITS Background Intelligent Transfer Service. Transfers files in the background using idle network bandwidth. Features such as Windows Update, Automatic Updates, and MSN Explorer depend on this service.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	qmgr.dll
  Dependencies:	RpcSs
  Failure action:	Restart service after 60 seconds

  
  
• Browser Computer Browser. Maintains an updated list of computers on the network and supplies this list to computers designated as browsers.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	browser.dll
  Dependencies:	lanmanworkstation, lanmanserver

  
  
• cisvc Indexing Service. Indexes contents and properties of files on local and remote computers; used for desktop search and Internet Information Services Server Extensions searching.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	cisvc.exe
  Dependencies:	RpcSs

  
  
• ClipSrv ClipBook. Enables ClipBook Viewer to store information and share it with remote computers. If the service is stopped, ClipBook Viewer will not be able to share information with remote computers.

  Start mode:	Disabled
  Login account:	LocalSystem
  DLL files:	catsrv.dll and comsvcs.dll, via COM+ and dllhost.exe
  Dependencies:	NetDDE

  
  
• COMSysApp COM+ System Application. Manages the configuration and tracking of Component Object Model COM+ components. Most COM+-based components depend on this service.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	dllhost.exe
  Dependencies:	RpcSs
  Failure action:	Restart service after 1 second, 5 seconds

  
  
• CryptSvc Cryptographic Services. Provides three management services: Catalog Database Service, which confirms the signatures of Windows files; Protected Root Service, which adds and removes Trusted Root Certification Authority certificates from this computer; and Key Service, which helps enroll the computer for certificates.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	cryptsvc.dll
  Dependencies:	RpcSs

  
  
• DcomLaunch DCOM Server Process Launcher. Provides launch functionality for DCOM services.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	rpcss.dll
  Load group:	Event Log
  Failure action:	REBOOT after 60 seconds

  
  
• Dhcp DHCP Client. Manages network configuration by registering and updating IP addresses and DNS names.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	dhcpcsvc.dll
  Load group:	TDI
  Dependencies:	Tcpip, AFD, NetBT

  
  
• dmadmin Logical Disk Manager Administrative Service. Configures hard disk drives and volumes. The service only runs for configuration processes and then stops.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	dmadmin.exe
  Dependencies:	RpcSs, PlugPlay, dmserver

  
  
• dmserver Logical Disk Manager. Detects and monitors new hard disk drives and sends disk volume information to Logical Disk Manager Administrative Service for configuration. Maintains configuration information for dynamic disks.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	dmserver.dll
  Dependencies:	RpcSs, PlugPlay

  
  
• Dnscache DNS Client. Resolves and caches Domain Name System (DNS) names for this computer.

  Start mode:	Auto
  Login account:	NetworkService
  DLL file:	dnsrslvr.dll
  Load group:	TDI
  Dependencies:	Tcpip

  
  
• ERSvc Error Reporting Service. Allows error reporting for services and applications running in nonstandard environments.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	ersvc.dll
  Dependencies:	RpcSs

  
  
• Eventlog Event Log. Enables event log messages issued by Windows-based programs and components to be viewed in Event Viewer. This service cannot be stopped. This service is provided directly by the Service Controller process.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	services.exe
  Load group:	Event log

  
  
• EventSystem COM+ Event System. Supports System Event Notification Service (SENS), which provides automatic distribution of events to subscribing Component Object Model (COM) components.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	es.dll
  Load group:	Network
  Dependencies:	RpcSs

  
  
• FastUserSwitchingCompatibility Fast User Switching Compatibility. Provides management for applications that require assistance in a multiple user environment.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	shsvcs.dll
  Dependencies:	TermService

  
  
• Fax Enables you to send and receive faxes, using fax resources available on this computer or on the network.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	fxssvc.exe
  Dependencies:	TapiSrv, RpcSs, PlugPlay, Spooler

  
  
• helpsvc Help and Support. Enables Help and Support Center to run on this computer.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	pchsvc.dll
  Dependencies:	RpcSs
  Failure action:	Restart service after 100 milliseconds

  
  
• HidServ HID Input Service. Enables generic input access to Human Interface Devices (HID), which activates and maintains the use of predefined hot buttons on keyboards, remote controls, and other multimedia devices.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	hidserv.dll
  Dependencies:	RpcSs

  
  
• HTTPFilter HTTP SSL. This service implements the secure hypertext transfer protocol (HTTPS) for the HTTP service, using the Secure Socket Layer (SSL).

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	w3ssl.dll
  Dependencies:	HTTP

  
  
• IISADMIN IIS Admin. Allows administration of web and FTP services through the Internet Information Services snap-in. Installed with IIS; not available on Windows XP Home Edition.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	inetinfo.exe
  Dependencies:	RpcSs, SamSs
  Failure action:	Run repair program after 1 millisecond

  
  
• ImapiService IMAPI CD-Burning COM Service. Manages CD recording using Image Mastering Applications Programming Interface (IMAPI).

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	imapi.exe

  
  
• Iprip RIP Listener. Listens for route updates sent by routers that use the Routing Information Protocol version 1 (RIPv1).

  Start mode:	Auto, when RIP network support is installed
  Login account:	LocalSystem
  DLL file:	iprip.dll
  Dependencies:	RpcSs

  
  
• irmon Infrared Monitor Service. Monitors an infrared (IrDA) interface for connections to other computers and devices; primarily used on laptops, PDAs, and printers.

  Startup mode:	Auto
  Login account:	LocalSystem
  DLL file:	irmon.dll

  
  
• lanmanserver Server. Supports file, print, and named-pipe sharing over the network for this computer. This service lets you share your folders and printers with other computers.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	srvsvc.dll

  
  
• lanmanworkstation Workstation. Creates and maintains client network connections to remote servers. This service lets you use folders and printers shared by other computers.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	wkssvc.dll
  Load group:	NetworkProvider

  
  
• LmHosts TCP/IP NetBIOS Helper. Enables support for NetBIOS over TCP/IP (NetBT) service and NetBIOS name resolution.

  Start mode:	Auto
  Login account:	LocalService
  DLL file:	lmhsvc.dll
  Load group:	TDI
  Dependencies:	NetBT, AFD

  
  
• LPDSVC TCP/IP Print Server. Provides a TCP/IP-based printing service that uses the Line Printer protocol. Installed as part of Print Services for UNIX.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	tcpsvcs.exe
  Dependencies:	Tcpip, Spooler

  
  
• Messenger Transmits "net send" and Alerter service messages between clients and servers. This service is used primarily for network administrators to notify users of system outages, or for the Performance Logs and Alerts service to notify system managers of system problems. It is not related to the Windows Messenger chat program. Starting with Windows XP Service Pack 2, this service is disabled by default, as it was abused by spammers to post pop-up ads.

  Start mode:	Disabled
  Login account:	LocalSystem
  DLL file:	msgsvc.dll
  Dependencies:	lanmanworkstation, NetBIOS, PlugPlay, RpcSs

  
  
• mnmsrvc NetMeeting Remote Desktop Sharing. Enables an authorized user to access this computer remotely by using NetMeeting over a corporate intranet.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	mnmsrvc.exe

  
  

  Note: This service can interact with the desktop.

• MSDTC Distributed Transaction Coordinator. Coordinates transactions that span multiple resource managers, such as databases, message queues, and file systems.

  Start mode:	Manual
  Login account:	NetworkService
  EXE file:	msdtc.exe
  Load group:	MS Transactions
  Dependencies:	RpcSs, SamSs

  
  
• MSFtpsvc FTP Publishing. Provides FTP connectivity and administration through the Internet Information Services snap-in. Installed with IIS; not available on Windows XP Home Edition.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	inetinfo.exe
  Dependencies:	IISADMIN

  
  
• MSIServer Windows Installer. The Windows installer service coordinates installation and removal of applications.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	msiexec.exe
  Dependencies:	RpcSs

  
  
• MSMQ Message Queuing. Provides a communications infrastructure for distributed, asynchronous messaging applications. Installed with optional Microsoft Message Queuing network component.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	mqsvc.exe
  Dependencies:	MQAC, RMCAST, lanmanserver, NtLmSsp, RpcSs, MSDTC

  
  
• MSMQTriggers Message Queuing Triggers. Associates the arrival of incoming messages at a queue with functionality in a COM component or a standalone executable program. Installed with optional Microsoft Message Queuing network component.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	mqtgsvc.exe
  Dependencies:	MSMQ

  
  
• NetDDE Network DDE. Provides network transport and security for Dynamic Data Exchange (DDE) for programs running on the same computer or on different computers.

  Start mode:	Disabled
  Login account:	LocalSystem
  EXE file:	netdde.exe
  Load group:	NetDDEGroup
  Dependencies:	NetDDEdsdm

  
  
• NetDDEdsdm Network DDE DSDM. Manages Dynamic Data Exchange (DDE) network shares.

  Start mode:	Disabled
  Login account:	LocalSystem
  EXE file:	netdde.exe

  
  
• Netlogon Net Logon. Supports pass-through authentication of account logon events for computers in a domain.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	lsass.exe
  Load group:	RemoteValidation
  Dependencies:	lanmanworkstation

  
  
• Netman Network Connections. Manages objects in the Network and Dial-Up Connections folder, in which you can view both local area network and remote connections.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	netman.dll
  Dependencies:	RpcSs

  
  

  Note: This service can interact with the desktop.

• Nla Network Location Awareness (NLA). Collects and stores network configuration and location information, and notifies applications when this information changes.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	mswsock.dll
  Dependencies:	Tcpip, AFD

  
  
• NtLmSsp NT LM Security Support Provider. Provides security to remote procedure call (RPC) programs that use transports other than named pipes.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	lsass.exe

  
  
• NtmsSvc Removable Storage. The Removable Storage service tracks and manages removable media such as tapes used for backups and archiving.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	ntmssvc.dll
  Dependencies:	RpcSs

  
  
• ose Office Source Engine. Saves installation files used for Microsoft Office updates and repairs and is required for the downloading of Setup updates and Watson error reports. (Installed as part of Microsoft Office.)

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	ose.exe

  
  
• p2pgasvc Peer Networking Group Authentication. Provides Network Authentication for Peer Group Members. Installed with optional Peer-to-Peer networking support.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	p2pgasvc.dll
  Dependencies:	p2pimsvc

  
  
• p2pimsvc Peer Networking Identity Manager. Provides Identity service for Peer Networking. Installed with optional Peer-to-Peer networking support.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	p2psvc.dll

  
  
• p2psvc Peer Networking. Provides Peer Networking services. Installed with optional Peer-to-Peer networking support.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	p2psvc.dll
  Dependencies:	PNRPSvc, p2pgasvc

  
  
• PlugPlay Plug and Play. Enables a computer to recognize and adapt to hardware changes with little or no user input. Stopping or disabling this service will result in system instability. This service is provided directly by the Service Controller process.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	services.exe
  Load group:	PlugPlay

  
  
• PNRPSvc Peer Name Resolution Protocol. Enables Serverless Peer Name Resolution over the Internet. Installed with optional Peer-to-Peer networking support.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	p2psvc.dll
  Dependencies:	Tcpip6, p2pimsvc

  
  
• PolicyAgent IPSEC Services. Manages IP security policy and starts the ISAKMP/Oakley (IKE) and the IP security driver.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	lsass.exe
  Dependencies:	RpcSs, Tcpip, IPSec

  
  
• ProtectedStorage Protected Storage. Provides protected storage for sensitive data, such as private keys, to prevent access by unauthorized services, processes, or users.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	lsass.exe
  Dependencies:	RpcSs

  
  

  Note: This service can interact with the desktop.

• RasAuto Remote Access Auto Connection Manager. Creates a connection to a remote network whenever a program references a remote DNS or NetBIOS name or address.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	rasauto.dll
  Dependencies:	RasMan, TapiSrv

  
  
• RasMan Remote Access Connection Manager. Makes and manages temporary network connections including modem dialup and PPPoE.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	rasmans.dll
  Dependencies:	TapiSrv

  
  
• RDSessMgr Remote Desktop Help Session Manager. Manages and controls Remote Assistance.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	sessmgr.exe
  Dependencies:	RpcSs

  
  
• RemoteAccess Routing and Remote Access. Offers routing services to businesses in local area and wide area network environments.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	mprdim.dll
  Dependencies:	RpcSs

  
  
• RemoteRegistry Remote Registry. Enables remote users to modify Registry settings on this computer. If this service is stopped, the Registry can be modified only by users on this computer.

  Start mode:	Auto
  Login account:	LocalService
  DLL file:	regsvc.dll
  Dependencies:	RpcSs
  Failure action:	Restart service after 1 second

  
  
• RpcLocator Remote Procedure Call (RPC) Locator. Manages the RPC name service database.

  Start mode:	Manual
  Login account:	NetworkService
  EXE file:	locator.exe
  Dependencies:	lanmanworkstation

  
  
• RpcSs Remote Procedure Call (RPC). Provides the endpoint mapper and other miscellaneous RPC services.

  Start mode:	Auto
  Login account:	NetworkService
  DLL file:	rpcss.dll
  Load group:	COM Infrastructure
  Failure action:	REBOOT after 60 seconds

  
  
• RSVP QoS RSVP. Provides network signaling and local traffic control setup functionality for QoS-aware programs and control applets.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	rsvp.exe
  Dependencies:	Tcpip, AFD, RpcSs

  
  
• SamSs Security Accounts Manager. Stores security information for local user accounts.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	lsass.exe
  Load group:	LocalValidation
  Dependencies:	RpcSs

  
  
• SCardSvr Smart Card. Manages access to smart cards read by this computer.

  Start mode:	Manual
  Login account:	LocalService
  EXE file:	scardsvr.exe
  Load group:	SmartCardGroup
  Dependencies:	PlugPlay

  
  
• Schedule Task Scheduler. Enables a user to configure and schedule automated tasks on this computer.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	schedsvc.dll
  Load group:	SchedulerGroup
  Dependencies:	RpcSs

  
  

  Note: This service can interact with the desktop.

• seclogon Secondary Logon. Enables starting processes under alternative credentials.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	seclogon.dll

  
  

  Note: This service can interact with the desktop.

• SENS System Event Notification. Tracks system events such as Windows logon, network, and power events. Notifies COM+ Event System subscribers of these events.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	sens.dll
  Load group:	Network
  Dependencies:	EventSystem

  
  
• SharedAccess Windows Firewall/Internet Connection Sharing (ICS). Provides network address translation, addressing, name resolution, and/or intrusion prevention services for a home or small office network.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	ipnathlp.dll
  Dependencies:	Netman, winmgmt

  
  
• ShellHWDetection Shell Hardware Detection. Provides notifications for AutoPlay hardware events.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	shsvcs.dll
  Load group:	ShellSvcGroup
  Dependencies:	RpcSs

  
  
• SimpTcp Simple TCP/IP Services. Supports the following TCP/IP services: Character Generator, Daytime, Discard, Echo, and Quote of the Day. Installed with Simple TCP/IP Services optional networking component.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	tcpsvcs.exe
  Dependencies:	AFD

  
  
• SMTPSVC Simple Mail Transfer Protocol (SMTP). Transports electronic mail across the network. Installed with IIS; not available on Windows XP Home Edition.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	inetinfo.exe
  Dependencies:	IISADMIN, Eventlog

  
  
• SNMP SNMP Service. Includes agents that monitor the activity in network devices and report to the network console workstation. Installed with the SNMP optional networking component.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	snmp.exe
  Dependencies:	Eventlog

  
  
• SNMPTRAP SNMP Trap Service. Receives trap messages generated by local or remote SNMP agents and forwards the messages to SNMP management programs running on this computer. Installed with the SNMP optional networking component.

  Start mode:	Manual
  Login account:	LocalService
  EXE file:	snmptrap.exe
  Dependencies:	Eventlog

  
  
• Spooler Print Spooler. Loads files to memory for later printing.

  Start mode:	Auto
  Login account:	LocalSystem
  EXE file:	spoolsv.exe
  Load group:	SpoolerGroup
  Dependencies:	RpcSs
  Failure action:	Restart service after 60 seconds

  
  

  Note: This service can interact with the desktop.

• srservice System Restore Service. Performs system restore functions. To stop service, turn off System Restore from the System Restore tab in My Computer, Properties

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	srsvc.dll
  Dependencies:	RpcSs

  
  
• SSDPSRV SSDP Discovery Service. Enables discovery of UPnP devices on your home network.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	ssdpsrv.dll
  Dependencies:	HTTP

  
  
• SSDPSRV SSDP Discovery Service. Enables discovery of UPnP devices on your home network. Installed with the Internet Gateway Device Discovery and Control Client optional networking component.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	ssdpsrv.dll
  Dependencies:	HTTP

  
  
• stisvc Windows Image Acquisition (WIA). Provides image acquisition services for scanners and cameras.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	wiaservc.dll
  Dependencies:	RpcSs

  
  
• SwPrv MS Software Shadow Copy Provider. Manages software-based volume shadow copies taken by the Volume Shadow Copy service. This service provides crucial support required by backup programs.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	swprv.dll, via COM+ and dllhost.exe
  Dependencies:	RpcSs

  
  
• SysmonLog Performance Logs and Alerts. Collects performance data from local or remote computers based on preconfigured schedule parameters; then writes the data to a log or triggers an alert.

  Start mode:	Manual
  Login account:	NetworkService
  EXE file:	smlogsvc.exe

  
  
• TapiSrv Telephony. Provides Telephony API (TAPI) support for programs that control telephony devices and IP-based voice connections on the local computer and, through the LAN, on servers that are also running the service.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	tapisrv.dll
  Dependencies:	PlugPlay, RpcSs

  
  
• TermService Terminal Services. Allows multiple users to be connected interactively to a machine as well as the display of desktops and applications to remote computers. The service provides the underpinning of Remote Desktop (including RD for Administrators), Fast User Switching, Remote Assistance, and Terminal Server.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	termsrv.dll
  Dependencies:	RpcSs

  
  
• Themes Provides user experience theme management.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	shsvcs.dll
  Load group:	UIGroup
  Failure action:	Restart service after 60 seconds

  
  
• TlntSvr Telnet. Enables a remote user to log on to this computer and run programs, and supports various TCP/IP Telnet clients, including UNIX-based and Windows-based computers.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	tlntsvr.exe

  
  
• TrkWks Distributed Link Tracking Client. Maintains links between NTFS files within a computer or across computers in a network domain.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	trkwks.dll
  Dependencies:	RpcSs

  
  
• UMWdf Windows User Mode Driver Framework. Enables Windows user mode drivers.

  Start mode:	Auto
  Login account:	LocalService
  EXE file:	wdfmgr.exe
  Dependencies:	RpcSs

  
  
• upnphost Universal Plug and Play Device Host. Provides support to host Universal Plug and Play devices.

  Start mode:	Manual
  Login account:	LocalService
  DLL file:	upnphost.dll
  Dependencies:	SSDPSRV, HTTP
  Failure action:	Restart the service immediately

  
  
• UPS Uninterruptible Power Supply. Manages an uninterruptible power supply (UPS) connected to the computer.

  Start mode:	Manual, or Auto if a UPS is installed
  Login account:	LocalSystem
  EXE file:	ups.exe

  
  
• VSS Volume Shadow Copy. Manages and implements Volume Shadow Copies used for backup and other purposes. This service provides crucial support required by backup programs.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	vssvc.exe
  Dependencies:	RpcSs

  
  
• W32Time Windows Time. Maintains date and time synchronization on all clients and servers in the network.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	w32time.dll
  Failure action:	Restart service after 60 seconds

  
  
• W3SVC World Wide Web Publishing. Provides web connectivity and administration through the Internet Information Services snap-in. Installed with IIS; not available on Windows XP Home Edition.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	inetinfo.exe
  Dependencies:	IISADMIN

  
  
• WebClient Enables Windows-based programs to create, access, and modify Internet-based files.

  Start mode:	Auto
  Login account:	LocalService
  DLL file:	webclnt.dll
  Load group:	NetworkProvider
  Dependencies:	MRxDAV

  
  
• winmgmt Windows Management Instrumentation. Provides a common interface and object model to access management information about operating system, devices, applications, and services. Most Windows management tools require this service.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	wmisvc.dll
  Dependencies:	RpcSs, Eventlog
  Failure action:	Restart service after 60 seconds

  
  
• WmcCds Windows Media Connect (WMC). Serves shared multimedia content to Universal Plug and Play devices. Installed as an optional downloadable extension to Windows Media Player.

  Start mode:	Manual
  Login account:	NetworkService
  EXE file:	mswmccds.exe
  Dependencies:	RpcSs, upnphost, WmcCdsLs

  
  
• WmcCdsLs Windows Media Connect (WMC) Helper. Monitors the network for new UPnP Media Renderer devices.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	mswmcls.exe
  Dependencies:	RpcSs

  
  
• WmdmPmSN Portable Media Serial Number Service. Retrieves the serial number of any portable media player connected to this computer. If this service is stopped, protected content might not be downloaded to the device.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	mspmsnsv.dll

  
  
• Wmi Windows Management Instrumentation Driver Extensions. Provides systems management information to and from drivers.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	advapi32.dll

  
  
• WmiApSrv WMI Performance Adapter. Provides performance library information from WMI "HiPerf" providers.

  Start mode:	Manual
  Login account:	LocalSystem
  EXE file:	wmiapsrv.exe
  Dependencies:	RpcSs

  
  
• wscsvc Security Center. Monitors system security settings and configurations. (Windows XP Service Pack 2 and later.)

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	wscsvc.dll
  Dependencies:	RpcSs, winmgmt

  
  
• wuauserv Automatic Updates. Enables the download and installation of critical Windows updates. If the service is disabled, the operating system must be manually updated at the Windows Update website.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	wuauserv.dll

  
  
• WZCSVC Wireless Zero Configuration. Provides automatic configuration for the 802.11 adapters.

  Start mode:	Auto
  Login account:	LocalSystem
  DLL file:	wzcsvc.dll
  Load group:	TDI
  Dependencies:	RpcSs, Ndisuio

  
  
• xmlprov Network Provisioning Service. Manages XML configuration files on a domain basis for automatic network provisioning.

  Start mode:	Manual
  Login account:	LocalSystem
  DLL file:	xmlprov.dll
  Dependencies:	RpcSs

  
  

Your computer may have services not listed in this table, as third-party drivers and application software may install additional services. They seem to add up quickly. For instance, I just checked my computer and it has 10 non-standard services installed:

• ATI Hotkey Poller and ATI Smart Installed with my ATI graphics adapter driver; monitors the keyboard for function keys set to change screen resolution or orientation.
• Cisco Systems, Inc. VPN Service A Virtual Private Network client that I use to securely connect to other networks over the Internet.
• Inadyn Dynamic DNS Update Client Updates the dyndns.org Domain Name Service when my network connection's IP address changes.
• iPod Service Installed with Apple's iTunes program; manages data synchronization between the computer and iPods.
• pcAnywhere Host Service Provides remote access, similar to Remote Desktop Connection, via the Symantec PCAnywhere program.
• PDEngine and PDScheduler Installed with the PerfectDisk disk defragmenting utility that I purchased.
• POP3Proxy A Perl script running as a Windows Service, which lets me filter my email through the SpamAssassin spam filter.
• SETI@Home controller Runs the SETI@Home data processing application (setiathome.ssl.berkeley.edu) as a Windows service, so that it runs 24x7 instead of just when I'm logged on.

In addition, other services may be installed as part of Windows in order to support nonstandard hardware.

Tip

If you don't recognize a service installed on your system, check www.sysinfo.org, which has an extensive database of programs and services found on Windows computers, including third-party applications, spyware, adware, and virus programs. It also might help to perform a Google search on the name of the unrecognized executable file.