diff --git a/internal/topdata/native.go b/internal/topdata/native.go
index ff7028c..14e8cec 100644
--- a/internal/topdata/native.go
+++ b/internal/topdata/native.go
@@ -865,6 +865,10 @@ func discoverNativeDatasets(dataDir string) ([]nativeDataset, error) {
 		if err != nil {
 			return err
 		}
+		lockPath := filepath.Join(rootPath, "lock.json")
+		if !plainDatasetNeedsLock(lockPath, tableData) {
+			lockPath = ""
+		}
 		outputName, _ := tableData["output"].(string)
 		if strings.TrimSpace(outputName) == "" {
 			outputName = nativeDatasetDefaultOutputName(filePath, nativeDatasetPlain)
@@ -874,7 +878,7 @@ func discoverNativeDatasets(dataDir string) ([]nativeDataset, error) {
 			Name:             filepath.ToSlash(relName),
 			RootPath:         rootPath,
 			BasePath:         filePath,
-			LockPath:         filepath.Join(rootPath, "lock.json"),
+			LockPath:         lockPath,
 			OutputName:       outputName,
 			Spec:             specForDataset(filepath.ToSlash(relName)),
 			CompareReference: optionalBool(tableData["compare_reference"], true),
@@ -979,6 +983,29 @@ func discoverNativeDatasets(dataDir string) ([]nativeDataset, error) {
 	return datasets, nil
 }
 
+func plainDatasetNeedsLock(lockPath string, tableData map[string]any) bool {
+	if _, err := os.Stat(lockPath); err == nil {
+		return true
+	}
+	rawRows, ok := tableData["rows"].([]any)
+	if !ok {
+		return false
+	}
+	for _, raw := range rawRows {
+		row, ok := raw.(map[string]any)
+		if !ok {
+			continue
+		}
+		key, hasKey := row["key"].(string)
+		if hasKey && strings.TrimSpace(key) != "" {
+			if _, hasID := row["id"]; !hasID {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 func discoverNativeOutputCatalog(dataDir string) (map[string]string, error) {
 	datasets, err := discoverNativeDatasets(dataDir)
 	if err != nil {
@@ -3396,9 +3423,13 @@ func collectPlainDataset(dataset nativeDataset) (nativeCollectedDataset, error)
 		return nativeCollectedDataset{}, fmt.Errorf("dataset %s: rows must be an array", dataset.Name)
 	}
 
-	lockData, err := loadLockfile(dataset.LockPath)
-	if err != nil {
-		return nativeCollectedDataset{}, fmt.Errorf("dataset %s: %w", dataset.Name, err)
+	lockData := map[string]int{}
+	if dataset.LockPath != "" {
+		var err error
+		lockData, err = loadLockfile(dataset.LockPath)
+		if err != nil {
+			return nativeCollectedDataset{}, fmt.Errorf("dataset %s: %w", dataset.Name, err)
+		}
 	}
 	usedIDs := map[int]struct{}{}
 	for _, rowID := range lockData {
diff --git a/internal/topdata/topdata_test.go b/internal/topdata/topdata_test.go
index 6f2b13e..04d6e95 100644
--- a/internal/topdata/topdata_test.go
+++ b/internal/topdata/topdata_test.go
@@ -3,6 +3,7 @@ package topdata
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -13544,6 +13545,67 @@ func TestBuildNativeSupportsLoosePlainTableAtTopdataDataRoot(t *testing.T) {
 	}
 }
 
+func TestBuildNativeDoesNotCreateRootLockfileForExplicitRootPlainTable(t *testing.T) {
+	root := testProjectRoot(t)
+	mkdirAll(t, filepath.Join(root, "topdata", "data"))
+	writeFile(t, filepath.Join(root, "topdata", "base_dialog.json"), "{}\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "categories.json"), `{
+  "output": "categories.2da",
+  "columns": ["Category"],
+  "rows": [
+    {"id": 1, "key": "categories:harmful", "Category": "Harmful"},
+    {"id": 2, "key": "categories:beneficial", "Category": "Beneficial"}
+  ]
+}`+"\n")
+
+	proj := testProject(root)
+	proj.Config.TopData.ReferenceBuilder = ""
+
+	result, err := BuildNativeWithOptions(proj, NativeBuildOptions{BuildWiki: false}, nil)
+	if err != nil {
+		t.Fatalf("expected explicit loose root table to build: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(result.Output2DADir, "categories.2da")); err != nil {
+		t.Fatalf("expected categories.2da output for loose root table: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(root, "topdata", "data", "lock.json")); !errors.Is(err, os.ErrNotExist) {
+		t.Fatalf("expected no root lock.json for fully explicit loose root table, got err %v", err)
+	}
+}
+
+func TestBuildNativeCreatesRootLockfileForImplicitRootPlainTableKeys(t *testing.T) {
+	root := testProjectRoot(t)
+	mkdirAll(t, filepath.Join(root, "topdata", "data"))
+	writeFile(t, filepath.Join(root, "topdata", "base_dialog.json"), "{}\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "categories.json"), `{
+  "output": "categories.2da",
+  "columns": ["Category"],
+  "rows": [
+    {"key": "categories:harmful", "Category": "Harmful"},
+    {"id": 5, "key": "categories:beneficial", "Category": "Beneficial"}
+  ]
+}`+"\n")
+
+	proj := testProject(root)
+	proj.Config.TopData.ReferenceBuilder = ""
+
+	if _, err := BuildNativeWithOptions(proj, NativeBuildOptions{BuildWiki: false}, nil); err != nil {
+		t.Fatalf("expected implicit loose root table to build: %v", err)
+	}
+
+	lockRaw, err := os.ReadFile(filepath.Join(root, "topdata", "data", "lock.json"))
+	if err != nil {
+		t.Fatalf("expected root lock.json for implicit keyed row: %v", err)
+	}
+	var lockData map[string]int
+	if err := json.Unmarshal(lockRaw, &lockData); err != nil {
+		t.Fatalf("unmarshal lockfile: %v", err)
+	}
+	if lockData["categories:harmful"] != 0 || lockData["categories:beneficial"] != 5 {
+		t.Fatalf("unexpected lock data: %#v", lockData)
+	}
+}
+
 func TestBuildNativeExtendsConfiguredPlainRowsByRepeatingLastLevel(t *testing.T) {
 	root := testProjectRoot(t)
 	mkdirAll(t, filepath.Join(root, "topdata", "data", "classes", "spellsgained"))