diff --git a/src/plugin-sdk/memory-host-events.test.ts b/src/plugin-sdk/memory-host-events.test.ts
index f2569f8c2cb..3f2dad57adb 100644
--- a/src/plugin-sdk/memory-host-events.test.ts
+++ b/src/plugin-sdk/memory-host-events.test.ts
@@ -232,6 +232,20 @@ describe("createPersistentDedupe", () => {
     ]);
   });
 
+  it("treats malformed legacy JSON cache files as empty", async () => {
+    const root = await createTempDir("openclaw-legacy-dedupe-malformed-");
+    const legacyPath = path.join(root, "legacy.json");
+    await fs.writeFile(legacyPath, "{not valid json");
+
+    await expect(
+      listPersistentDedupeLegacyJsonFileEntries({
+        filePath: legacyPath,
+        ttlMs: 500,
+        now: 1_100,
+      }),
+    ).resolves.toStrictEqual([]);
+  });
+
   it("warms empty namespaces and ignores retired JSON cache files", async () => {
     const root = await createTempDir("openclaw-dedupe-");
     const emptyReader = createDedupe(root, { ttlMs: 10_000 });
diff --git a/src/plugin-sdk/persistent-dedupe.ts b/src/plugin-sdk/persistent-dedupe.ts
index 9e73ff3a7be..8231db8f800 100644
--- a/src/plugin-sdk/persistent-dedupe.ts
+++ b/src/plugin-sdk/persistent-dedupe.ts
@@ -326,7 +326,12 @@ function parseLegacyDedupeData(raw: string): {
   data: Record<string, number>;
   invalidCount: number;
 } {
-  const parsed = JSON.parse(raw) as unknown;
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(raw) as unknown;
+  } catch {
+    return { data: {}, invalidCount: 0 };
+  }
   if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) {
     return { data: {}, invalidCount: 0 };
   }