diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a86080b7..8b724ac0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -867,6 +867,18 @@ jobs:
               Start-Sleep -Seconds 2
           } while ($true)
 
+          # Storage Spaces Direct clusters have a Health resource (type "Health
+          # Service") that answers CLUSCTL_RESOURCE_GET_CLASS_INFO with only the
+          # class DWORD (#2669). S2D itself claims every disk of an allowed bus
+          # type, and marking the other VHDX disks as not claimable removes them
+          # from the host, which breaks the other steps. Disks from a loopback
+          # iSCSI target vanish when the node joins the cluster, because the
+          # iSCSI Target Server then only serves clustered targets. So register
+          # the resource directly. It stays offline without S2D.
+          if ($null -eq (Get-ClusterResource -Name "Health" -ErrorAction SilentlyContinue)) {
+              Add-ClusterResource -Name "Health" -ResourceType "Health Service" -Group "Cluster Group" | Out-Null
+          }
+
           Get-Cluster | Format-List Name, AdministrativeAccessPoint
           Get-ClusterNode | Format-Table Name, State, NodeWeight, DynamicWeight
           Get-ClusterNetwork | Format-Table Name, State, Role, Address
diff --git a/internal/collector/mscluster/AGENTS.md b/internal/collector/mscluster/AGENTS.md
index 4702c175..f0c02b56 100644
--- a/internal/collector/mscluster/AGENTS.md
+++ b/internal/collector/mscluster/AGENTS.md
@@ -27,6 +27,17 @@
   two groups (`CIResources`, `CIFailedResources`) on a private network of an
   internal Hyper-V switch; the parity tests require them. It has no clustered
   disks, so shared volume parity still compares empty sets.
+  The "Cluster Group" also holds an offline "Health Service" resource
+  without Storage Spaces Direct. It answers `CLUSCTL_RESOURCE_GET_CLASS_INFO`
+  with only 4 bytes, like the Health resource of S2D clusters (#2669). S2D
+  itself cannot be enabled on the runner: it claims every VHDX disk of the
+  other steps, and `Set-ClusterStorageSpacesDirectDisk -CanBeClaimed $false`
+  removes those disks from the host instead of leaving them alone. Disks from
+  a loopback iSCSI target (with `S2DBusTypes` limited to iSCSI) appear before
+  `New-Cluster`, but the session and the target are gone after it: once the
+  node is clustered, the iSCSI Target Server only serves clustered targets.
+  A clustered target needs a cluster disk for its files, and
+  `Get-ClusterAvailableDisk` does not list a host-mounted VHDX.
 - Property lists returned by the cluster service end with an extra
   `CLUSPROP_SYNTAX_ENDMARK` after the last value list; fixtures built only from
   the documentation miss this. The parser validates only the structure and