diff --git a/internal/hostagent/unraid.go b/internal/hostagent/unraid.go
index 446074e7d..20c77ef3f 100644
--- a/internal/hostagent/unraid.go
+++ b/internal/hostagent/unraid.go
@@ -522,10 +522,10 @@ func isUnraidEmptySlot(disk agentshost.UnraidDisk) bool {
 	// Unraid names every configured slot (for example disk6 or parity2), even
 	// when it has never been assigned. A slot label is therefore topology, not
 	// membership evidence. Preserve DISK_NP members only when native identity,
-	// device, filesystem, or size evidence shows that a disk was assigned.
+	// device, a concrete filesystem, or size evidence shows that a disk was assigned.
 	return strings.TrimSpace(disk.Device) == "" &&
 		!unraidstatus.HasMeaningfulIdentity(disk.Model, disk.Serial) &&
-		strings.TrimSpace(disk.Filesystem) == "" &&
+		!unraidstatus.HasMeaningfulFilesystem(disk.Filesystem) &&
 		disk.SizeBytes == 0
 }
 
diff --git a/internal/hostagent/unraid_test.go b/internal/hostagent/unraid_test.go
index 2f5d92b57..a5fb58621 100644
--- a/internal/hostagent/unraid_test.go
+++ b/internal/hostagent/unraid_test.go
@@ -154,6 +154,7 @@ diskNumber.5=5
 diskName.5=disk5
 diskSize.5=0
 diskId.5=ata-_
+diskFsType.5=auto
 rdevStatus.5=DISK_NP
 rdevName.5=
 rdevId.5=ata-_
@@ -161,6 +162,7 @@ diskNumber.29=29
 diskName.29=parity2
 diskSize.29=0
 diskId.29=ata-_
+diskFsType.29=auto
 rdevStatus.29=DISK_NP_DSBL
 rdevName.29=
 rdevId.29=ata-_
@@ -286,6 +288,7 @@ id="ata-_"
 size="0"
 status="DISK_NP"
 type="Data"
+fsType="auto"
 ["parity2"]
 idx="29"
 name="parity2"
@@ -294,6 +297,7 @@ id="ata-_"
 size="0"
 status="DISK_NP_DSBL"
 type="Parity"
+fsType="auto"
 `
 
 	disks := parseUnraidDisksINI(input)
diff --git a/internal/monitoring/monitor_agents.go b/internal/monitoring/monitor_agents.go
index 7c099846f..56a5cf1da 100644
--- a/internal/monitoring/monitor_agents.go
+++ b/internal/monitoring/monitor_agents.go
@@ -4147,7 +4147,7 @@ func isLegacyUnraidEmptySlot(disk agentshost.UnraidDisk, normalizedStatus string
 	}
 	return strings.TrimSpace(disk.Device) == "" &&
 		!unraidstatus.HasMeaningfulIdentity(disk.Model, disk.Serial) &&
-		strings.TrimSpace(disk.Filesystem) == "" &&
+		!unraidstatus.HasMeaningfulFilesystem(disk.Filesystem) &&
 		disk.SizeBytes == 0
 }
 
diff --git a/internal/monitoring/monitor_host_agents_test.go b/internal/monitoring/monitor_host_agents_test.go
index e2ce84fa3..95c0d8c3b 100644
--- a/internal/monitoring/monitor_host_agents_test.go
+++ b/internal/monitoring/monitor_host_agents_test.go
@@ -2588,8 +2588,8 @@ func TestApplyHostReportFiltersLegacyUnraidEmptySlots(t *testing.T) {
 			Disks: []agentshost.UnraidDisk{
 				{Name: "parity", Device: "/dev/sdb", Role: "parity", RawStatus: "DISK_OK", SizeBytes: 5860522532},
 				{Name: "disk1", Device: "/dev/sde", Role: "data", RawStatus: "DISK_OK", SizeBytes: 5860522532},
-				{Name: "disk6", Role: "data", RawStatus: "DISK_NP", Model: "ata -", Serial: "ata-_", Slot: 6},
-				{Name: "parity2", Role: "parity", RawStatus: "DISK_NP_DSBL", Model: "ata -", Serial: "ata-_", Slot: 29},
+				{Name: "disk6", Role: "data", Status: "missing", RawStatus: "DISK_NP", Model: "ata -", Serial: "ata-_", Filesystem: "auto", Slot: 6},
+				{Name: "parity2", Role: "parity", Status: "missing", RawStatus: "DISK_NP_DSBL", Model: "ata -", Serial: "ata-_", Filesystem: "auto", Slot: 29},
 			},
 		},
 		Timestamp: time.Now().UTC(),
diff --git a/internal/unraid/status.go b/internal/unraid/status.go
index 2ea54e51e..4836caf14 100644
--- a/internal/unraid/status.go
+++ b/internal/unraid/status.go
@@ -31,6 +31,15 @@ func HasMeaningfulIdentity(model, serial string) bool {
 	return NormalizeNativeIdentity(model) != "" || NormalizeNativeIdentity(serial) != ""
 }
 
+// HasMeaningfulFilesystem reports whether a native filesystem field is
+// evidence that a slot has a disk assigned. Unraid emits "auto" for configured
+// but empty DISK_NP slots, so presence of that value alone cannot establish
+// membership.
+func HasMeaningfulFilesystem(filesystem string) bool {
+	filesystem = strings.TrimSpace(filesystem)
+	return filesystem != "" && !strings.EqualFold(filesystem, "auto")
+}
+
 // IsExplicitMissingMember reports Unraid's provider-owned status for a slot
 // that was assigned but whose device is no longer present. Plain DISK_NP means
 // no device is assigned and must not be treated as equivalent.
diff --git a/internal/unraid/status_test.go b/internal/unraid/status_test.go
index 8c5be0c36..c97202727 100644
--- a/internal/unraid/status_test.go
+++ b/internal/unraid/status_test.go
@@ -35,3 +35,18 @@ func TestIsExplicitMissingMember(t *testing.T) {
 		}
 	}
 }
+
+func TestHasMeaningfulFilesystem(t *testing.T) {
+	t.Parallel()
+
+	for _, filesystem := range []string{"", "auto", " AUTO "} {
+		if HasMeaningfulFilesystem(filesystem) {
+			t.Errorf("%q must not establish Unraid disk assignment", filesystem)
+		}
+	}
+	for _, filesystem := range []string{"xfs", "btrfs", "luks:xfs"} {
+		if !HasMeaningfulFilesystem(filesystem) {
+			t.Errorf("%q must establish Unraid disk assignment", filesystem)
+		}
+	}
+}