“ERROR: Machine is offline or invalid” in adsysdis.log and the SMS Executive service on the Site Server stops unexpectedly

I am trying to Active Directory System Discovery but when it does the SMS Executive service on my Site Server stops unexpectedly.

If I look the adsysdis.log I see the following lines repeated over and over again:

GetIPAddr – Host not found resolving FQDN “”.
GetIPAddr – Retry with system name “”…

ERROR: Machine is offline or invalid.

Why am I unable to configure Network Discovery to discover a DHCP Server in my environment?

For some reason I am unable to configure Network Discovery to discover a DHCP Server in my environment.

Why are DDRs still being generated by Mobile Device Clients when I’ve disabled Heartbeat Discovery?

I have disabled Heartbeat Discovery but for some reason my Mobile Device Clients are still generating Discovery Data Records (DDRs).

Why doesn’t the Heartbeat Discovery Record included the ConfigMgr Client version?

I’ve noticed for some reason that the Heartbeat Discovery Data Record doesn’t include the version of the ConfigMgr Client.

Why isn’t Network Discovery discovering any computers from the Local Domain?

I’ve enabled Network Discovery but for some reason it’s not discovering any computers from the local Domain.

Why is Network Discovery failing to discover Domain and DHCP servers?

I’ve enabled Network Discovery but for some reason it’s failing to discover Domain and DHCP servers.

Why doesn’t Delta Discovery delete resources from Collections in ConfigMgr 2012 SP2/ R2 SP1?

I have Delta Discovery enabled in my environment.

For some reason when I remove a User or Computer from a Security Group that has previously been discovered, Delta Discovery doesn’t pick up the deletion and remove the resource from the Collection.

If I wait for a Full discovery to run then the resources are removed correctly.

Why does Active Directory Group Discovery generate lots of DDRs?

I am running Active Directory Group Discovery but it seems to be generating lots of Discovery Data Records (DDRs).

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What is the “SMS_WINNT_SERVER_DISCOVERY_AGENT” Component?

I’ve noticed that if I run Configuration Manager Service Manager on any of your Site System Servers I see a thread of the SMS_EXECUTIVE service called SMS_WINNT_SERVER_DISCOVERY_AGENT – what is this?

Why isn’t Network Discovery discovering my resources?

I’ve enabled Network Discovery but it’s not discovering some of my resources.