Recipe 10.22. Viewing the Service Load Order

Problem

You want to view the order in which services load during system startup. You typically don't need to worry about the service load order, but it can be helpful if you are experiencing problems with services that are not starting correctly after reboot. Something else to note is that device drivers are treated like services. So by viewing the service load order, you can see the device driver load order as well.

Solution

Using downloadable software

Open the Sysinternals LoadOrd (loadord.exe) utility. See Figure 10-3 for an example of the output.

Figure 10-3. LoadOrd utility

Discussion

As we described in Recipe 10.21, Windows supports the concept of service dependencies whereby a service cannot start until the services it depends on have started successfully. Windows also supports the notion of a service load order so that services and groups of services start in a particular order.

A service group is a collection of services that are loaded together at system startup. For example, Figure 10-3 shows particular service groups listed under the Group Name column. The complete list of service groups can be found in the Registry under the following key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GroupOrderList

Not all services are part of a group, and the ones that are load before the ones that aren't. The following Registry value contains a list of service groups in the order of how they are loaded:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ServiceGroupOrder\List

Each service has Registry values under its specific Registry key (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\System\Services\<ServiceName>) that determine which group it is a member of (if any) and its dependencies. Here is a list of them:

Group

REG_SZ value that contains the service group name the service belongs to

Tag

REG_DWORD value that contains a number that dictates the relative order the service starts within a service group

DependOnGroup

REG_MULTI_SZ value that contains the service groups that must load successfully before this service can start

DependOnService

REG_MULTI_SZ value that contains the services that must load successfully before this service can start

See Also

MS KB 115486, "HOWTO: Control Device Driver Load Order," and MS KB 193888, "How to Delay Loading of Specific Services"