diff --git a/bme-sync.js b/bme-sync.js
index a3c8f03..d6f5585 100644
--- a/bme-sync.js
+++ b/bme-sync.js
@@ -49,6 +49,23 @@ function normalizeRemoteFilenameCandidate(fileName, fallbackValue = "ST-BME_sync
   return sanitized || fallbackValue;
 }
 
+function normalizeLegacyRemoteFilenameCandidate(
+  fileName,
+  fallbackValue = "ST-BME_sync_unknown.json",
+) {
+  const raw = String(fileName ?? "");
+  const normalized =
+    typeof raw.normalize === "function" ? raw.normalize("NFKD") : raw;
+  const sanitized = normalized
+    .replace(/[\u0300-\u036f]/g, "")
+    .replace(/[^A-Za-z0-9._~-]+/g, "_")
+    .replace(/_+/g, "_")
+    .replace(/^\.+/g, "")
+    .slice(0, BME_SYNC_FILENAME_MAX_LENGTH)
+    .trim();
+  return sanitized || fallbackValue;
+}
+
 function buildSyncFilename(chatId) {
   const normalizedChatId = normalizeChatId(chatId);
   const legacyName = `${BME_SYNC_FILE_PREFIX}${normalizedChatId}${BME_SYNC_FILE_SUFFIX}`;
@@ -74,6 +91,18 @@ function buildSyncFilename(chatId) {
   return `${core}${BME_SYNC_FILE_SUFFIX}`;
 }
 
+function buildLegacyRawSyncFilename(chatId) {
+  return `${BME_SYNC_FILE_PREFIX}${normalizeChatId(chatId)}${BME_SYNC_FILE_SUFFIX}`;
+}
+
+function rememberResolvedSyncFilename(chatId, filename) {
+  const normalizedChatId = normalizeChatId(chatId);
+  const normalizedFilename = String(filename || "").trim();
+  if (!normalizedChatId || !normalizedFilename) return "";
+  sanitizedFilenameByChatId.set(normalizedChatId, normalizedFilename);
+  return normalizedFilename;
+}
+
 function normalizeRevision(value) {
   const parsed = Number(value);
   if (!Number.isFinite(parsed) || parsed < 0) return 0;
@@ -933,28 +962,56 @@ async function sanitizeFilename(fileName, options = {}) {
   }
 
   try {
-    const fetchImpl = getFetch(options);
-    const response = await fetchImpl("/api/files/sanitize-filename", {
-      method: "POST",
-      headers: {
-        ...getRequestHeadersSafe(options),
-        "Content-Type": "application/json",
-      },
-      body: JSON.stringify({ fileName }),
-    });
-
-    if (!response.ok) {
-      return finalFallback;
-    }
-
-    const payload = await response.json().catch(() => null);
-    const sanitized = String(payload?.fileName || "").trim();
+    const sanitized = await requestSanitizedFilename(fileName, options);
     return normalizeRemoteFilenameCandidate(sanitized, finalFallback);
   } catch {
     return finalFallback;
   }
 }
 
+async function requestSanitizedFilename(fileName, options = {}) {
+  if (options.disableRemoteSanitize) {
+    return String(fileName || "");
+  }
+
+  const fetchImpl = getFetch(options);
+  const response = await fetchImpl("/api/files/sanitize-filename", {
+    method: "POST",
+    headers: {
+      ...getRequestHeadersSafe(options),
+      "Content-Type": "application/json",
+    },
+    body: JSON.stringify({ fileName }),
+  });
+
+  if (!response.ok) {
+    return "";
+  }
+
+  const payload = await response.json().catch(() => null);
+  return String(payload?.fileName || "").trim();
+}
+
+async function resolveLegacySyncFilename(chatId, options = {}) {
+  const normalizedChatId = normalizeChatId(chatId);
+  const rawFileName = buildLegacyRawSyncFilename(normalizedChatId);
+  const legacyFallback = normalizeLegacyRemoteFilenameCandidate(
+    rawFileName,
+    "ST-BME_sync_unknown.json",
+  );
+
+  if (options.disableRemoteSanitize) {
+    return legacyFallback;
+  }
+
+  try {
+    const sanitized = await requestSanitizedFilename(rawFileName, options);
+    return normalizeLegacyRemoteFilenameCandidate(sanitized, legacyFallback);
+  } catch {
+    return legacyFallback;
+  }
+}
+
 async function resolveSyncFilename(chatId, options = {}) {
   const normalizedChatId = normalizeChatId(chatId);
   if (!normalizedChatId) {
@@ -968,10 +1025,41 @@ async function resolveSyncFilename(chatId, options = {}) {
   const rawFileName = buildSyncFilename(normalizedChatId);
   const sanitized = await sanitizeFilename(rawFileName, options);
   const finalName = normalizeRemoteFilenameCandidate(sanitized, rawFileName);
-  sanitizedFilenameByChatId.set(normalizedChatId, finalName);
+  rememberResolvedSyncFilename(normalizedChatId, finalName);
   return finalName;
 }
 
+async function resolveSyncFilenameCandidates(chatId, options = {}) {
+  const normalizedChatId = normalizeChatId(chatId);
+  if (!normalizedChatId) {
+    throw new Error("chatId 不能为空");
+  }
+
+  const candidates = [];
+  const pushCandidate = (value) => {
+    const normalizedValue = String(value || "").trim();
+    if (!normalizedValue || candidates.includes(normalizedValue)) return;
+    candidates.push(normalizedValue);
+  };
+
+  if (sanitizedFilenameByChatId.has(normalizedChatId)) {
+    pushCandidate(sanitizedFilenameByChatId.get(normalizedChatId));
+  }
+
+  const primaryRawFileName = buildSyncFilename(normalizedChatId);
+  const primarySanitized = await sanitizeFilename(primaryRawFileName, options);
+  pushCandidate(
+    normalizeRemoteFilenameCandidate(primarySanitized, primaryRawFileName),
+  );
+
+  const legacyRawFileName = buildLegacyRawSyncFilename(normalizedChatId);
+  if (legacyRawFileName !== primaryRawFileName) {
+    pushCandidate(await resolveLegacySyncFilename(normalizedChatId, options));
+  }
+
+  return candidates;
+}
+
 async function readRemoteSnapshot(chatId, options = {}) {
   const normalizedChatId = normalizeChatId(chatId);
   if (!normalizedChatId) {
@@ -983,70 +1071,81 @@ async function readRemoteSnapshot(chatId, options = {}) {
     };
   }
 
-  const filename = await resolveSyncFilename(normalizedChatId, options);
   const fetchImpl = getFetch(options);
-  const cacheBust = `t=${Date.now()}`;
-  const url = `/user/files/${encodeURIComponent(filename)}?${cacheBust}`;
+  const candidateFilenames = await resolveSyncFilenameCandidates(
+    normalizedChatId,
+    options,
+  );
+  let lastNotFoundFilename = candidateFilenames[0] || "";
 
-  let response;
-  try {
-    response = await fetchImpl(url, {
-      method: "GET",
-      cache: "no-store",
-    });
-  } catch (error) {
-    console.warn("[ST-BME] 读取远端同步文件失败:", error);
-    return {
-      exists: false,
-      status: "network-error",
-      filename,
-      snapshot: null,
-      error,
-    };
+  for (const filename of candidateFilenames) {
+    const cacheBust = `t=${Date.now()}`;
+    const url = `/user/files/${encodeURIComponent(filename)}?${cacheBust}`;
+
+    let response;
+    try {
+      response = await fetchImpl(url, {
+        method: "GET",
+        cache: "no-store",
+      });
+    } catch (error) {
+      console.warn("[ST-BME] 读取远端同步文件失败:", error);
+      return {
+        exists: false,
+        status: "network-error",
+        filename,
+        snapshot: null,
+        error,
+      };
+    }
+
+    if (response.status === 404) {
+      lastNotFoundFilename = filename;
+      continue;
+    }
+
+    if (!response.ok) {
+      const errorText = await response.text().catch(() => response.statusText);
+      const error = new Error(errorText || `HTTP ${response.status}`);
+      console.warn("[ST-BME] 读取远端同步文件失败:", error);
+      return {
+        exists: false,
+        status: "http-error",
+        filename,
+        snapshot: null,
+        error,
+        statusCode: response.status,
+      };
+    }
+
+    try {
+      const remotePayload = await response.json();
+      const snapshot = normalizeSyncSnapshot(remotePayload, normalizedChatId);
+      rememberResolvedSyncFilename(normalizedChatId, filename);
+      return {
+        exists: true,
+        status: "ok",
+        filename,
+        snapshot,
+      };
+    } catch (error) {
+      console.warn("[ST-BME] 解析远端同步文件失败:", error);
+      return {
+        exists: false,
+        status: "invalid-json",
+        filename,
+        snapshot: null,
+        error,
+      };
+    }
   }
 
-  if (response.status === 404) {
-    return {
-      exists: false,
-      status: "not-found",
-      filename,
-      snapshot: null,
-    };
-  }
-
-  if (!response.ok) {
-    const errorText = await response.text().catch(() => response.statusText);
-    const error = new Error(errorText || `HTTP ${response.status}`);
-    console.warn("[ST-BME] 读取远端同步文件失败:", error);
-    return {
-      exists: false,
-      status: "http-error",
-      filename,
-      snapshot: null,
-      error,
-      statusCode: response.status,
-    };
-  }
-
-  try {
-    const remotePayload = await response.json();
-    const snapshot = normalizeSyncSnapshot(remotePayload, normalizedChatId);
-    return {
-      exists: true,
-      status: "ok",
-      filename,
-      snapshot,
-    };
-  } catch (error) {
-    console.warn("[ST-BME] 解析远端同步文件失败:", error);
-    return {
-      exists: false,
-      status: "invalid-json",
-      filename,
-      snapshot: null,
-      error,
-    };
-  }
+  return {
+    exists: false,
+    status: "not-found",
+    filename: lastNotFoundFilename,
+    snapshot: null,
+  };
 }
 
 async function writeSnapshotToRemote(snapshot, chatId, options = {}) {
@@ -1671,37 +1770,48 @@ export async function deleteRemoteSyncFile(chatId, options = {}) {
   }
 
   try {
-    const filename = await resolveSyncFilename(normalizedChatId, options);
     const fetchImpl = getFetch(options);
-    const response = await fetchImpl("/api/files/delete", {
-      method: "POST",
-      headers: {
-        ...getRequestHeadersSafe(options),
-        "Content-Type": "application/json",
-      },
-      body: JSON.stringify({
-        path: `/user/files/${filename}`,
-      }),
-    });
+    const filenames = await resolveSyncFilenameCandidates(
+      normalizedChatId,
+      options,
+    );
+    let lastNotFoundFilename = filenames[0] || "";
 
-    if (response.status === 404) {
+    for (const filename of filenames) {
+      const response = await fetchImpl("/api/files/delete", {
+        method: "POST",
+        headers: {
+          ...getRequestHeadersSafe(options),
+          "Content-Type": "application/json",
+        },
+        body: JSON.stringify({
+          path: `/user/files/${filename}`,
+        }),
+      });
+
+      if (response.status === 404) {
+        lastNotFoundFilename = filename;
+        continue;
+      }
+
+      if (!response.ok) {
+        const errorText = await response.text().catch(() => response.statusText);
+        throw new Error(errorText || `HTTP ${response.status}`);
+      }
+
+      sanitizedFilenameByChatId.delete(normalizedChatId);
       return {
-        deleted: false,
+        deleted: true,
         chatId: normalizedChatId,
         filename,
-        reason: "not-found",
       };
     }
 
-    if (!response.ok) {
-      const errorText = await response.text().catch(() => response.statusText);
-      throw new Error(errorText || `HTTP ${response.status}`);
-    }
-
     return {
-      deleted: true,
+      deleted: false,
       chatId: normalizedChatId,
-      filename,
+      filename: lastNotFoundFilename,
+      reason: "not-found",
     };
   } catch (error) {
     console.warn("[ST-BME] 删除远端同步文件失败:", error);
diff --git a/ena-planner/ena-planner.js b/ena-planner/ena-planner.js
index 7171923..bd282ab 100644
--- a/ena-planner/ena-planner.js
+++ b/ena-planner/ena-planner.js
@@ -1203,7 +1203,7 @@ async function buildPlannerMessages(rawUserInput) {
     // Extra user blocks before user message
     for (const b of enaUserBlocks) {
         const content = await renderTemplateAll(b.content, env, messageVars);
-        messages.splice(Math.max(0, messages.length - 1), 0, { role: 'system', content: `【extra-user-block】\n${content}` });
+        messages.splice(Math.max(0, messages.length - 1), 0, { role: 'user', content: `【extra-user-block】\n${content}` });
     }
 
     // 7) Assistant blocks
diff --git a/hide-engine.js b/hide-engine.js
index 0b16ab8..7eef184 100644
--- a/hide-engine.js
+++ b/hide-engine.js
@@ -170,9 +170,69 @@ function clearManagedState() {
   hideState.lastProcessedLength = 0;
 }
 
-function restoreManagedSystemFlags(chat, runtime = {}) {
-  if (!Array.isArray(chat) || hideState.managedSystemIndices.size === 0) {
+function isManagedSystemMessage(message) {
+  return Boolean(
+    message?.is_system === true &&
+      message?.extra &&
+      typeof message.extra === "object" &&
+      message.extra[BME_HIDE_HASH_MARKER] === true,
+  );
+}
+
+function collectManagedSystemIndices(chat) {
+  if (!Array.isArray(chat) || chat.length === 0) return [];
+  const indices = [];
+  for (let index = 0; index < chat.length; index++) {
+    if (isManagedSystemMessage(chat[index])) {
+      indices.push(index);
+    }
+  }
+  return indices;
+}
+
+function hydrateManagedStateFromChat(
+  chat,
+  chatKey = getCurrentChatKey(),
+  { bootstrapLength = false } = {},
+) {
+  if (!Array.isArray(chat)) {
     hideState.managedSystemIndices.clear();
+    hideState.hiddenRangeEnd = -1;
+    return { managedCount: 0, hiddenRangeEnd: -1 };
+  }
+
+  const managedIndices = collectManagedSystemIndices(chat);
+  hideState.managedSystemIndices.clear();
+  for (const index of managedIndices) {
+    hideState.managedSystemIndices.add(index);
+  }
+
+  hideState.managedChatRef = chat;
+  hideState.managedChatKey = chatKey;
+  hideState.hiddenRangeEnd =
+    managedIndices.length > 0 ? managedIndices[managedIndices.length - 1] : -1;
+  if (managedIndices.length > 0 && bootstrapLength) {
+    hideState.lastProcessedLength = chat.length;
+  }
+
+  return {
+    managedCount: managedIndices.length,
+    hiddenRangeEnd: hideState.hiddenRangeEnd,
+  };
+}
+
+function restoreManagedSystemFlags(chat, runtime = {}) {
+  if (!Array.isArray(chat)) {
+    hideState.managedSystemIndices.clear();
+    return 0;
+  }
+
+  if (hideState.managedSystemIndices.size === 0) {
+    hydrateManagedStateFromChat(chat, getCurrentChatKey(runtime), {
+      bootstrapLength: false,
+    });
+  }
+  if (hideState.managedSystemIndices.size === 0) {
     return 0;
   }
 
@@ -279,11 +339,22 @@ async function runHideApply(settings = {}, runtime = {}, options = {}) {
 
   const chatKey = getCurrentChatKey(runtime);
   const previousChatKey = hideState.managedChatKey;
+  const hadTrackedState =
+    hideState.managedSystemIndices.size > 0 ||
+    hideState.hiddenRangeEnd >= 0 ||
+    (Number.isFinite(hideState.lastProcessedLength) &&
+      hideState.lastProcessedLength > 0);
+  adoptManagedChat(chat, chatKey, runtime);
+  hydrateManagedStateFromChat(chat, chatKey, {
+    bootstrapLength: !hadTrackedState,
+  });
   const sameChat =
     previousChatKey !== null && chatKey !== null && previousChatKey === chatKey;
-  const previousHiddenEnd = sameChat ? hideState.hiddenRangeEnd : -1;
-  const previousLength = sameChat ? hideState.lastProcessedLength : 0;
-  adoptManagedChat(chat, chatKey, runtime);
+  const previousHiddenEnd = hideState.hiddenRangeEnd;
+  const previousLength =
+    sameChat && Number.isFinite(hideState.lastProcessedLength)
+      ? hideState.lastProcessedLength
+      : 0;
   hideState.lastProcessedLength = chatLength;
 
   if (!normalized.enabled || normalized.hideLastN <= 0) {
@@ -435,6 +506,9 @@ export async function unhideAll(runtime = {}) {
     return buildResult({ chatLength });
   }
 
+  hydrateManagedStateFromChat(chatInfo.chat, getCurrentChatKey(runtime), {
+    bootstrapLength: false,
+  });
   const { shownCount } = await unhideCurrentRange(runtime, version, {
     full: true,
   });
@@ -454,6 +528,12 @@ export async function unhideAll(runtime = {}) {
 export function resetHideState(runtime = {}) {
   clearScheduledTimer(runtime);
   beginOperation();
+  const chatInfo = getCurrentChatInfo(runtime);
+  if (Array.isArray(chatInfo.chat)) {
+    hydrateManagedStateFromChat(chatInfo.chat, chatInfo.chatId || null, {
+      bootstrapLength: false,
+    });
+  }
   restoreManagedSystemFlags(hideState.managedChatRef, runtime);
   clearManagedState();
 }
diff --git a/tests/hide-engine.mjs b/tests/hide-engine.mjs
index 52514d9..33745f9 100644
--- a/tests/hide-engine.mjs
+++ b/tests/hide-engine.mjs
@@ -144,9 +144,40 @@ async function testResetClearsStateWithoutIssuingCommands() {
   });
 }
 
+async function testUnhideAllRecoversPersistedManagedMarkersAfterStateLoss() {
+  resetHideState();
+  const chat = [
+    {
+      mes: "user-1",
+      is_user: true,
+      is_system: true,
+      extra: { __st_bme_hide_managed: true },
+    },
+    {
+      mes: "assistant-1",
+      is_user: false,
+      is_system: true,
+      extra: { __st_bme_hide_managed: true },
+    },
+    { mes: "user-2", is_user: true, is_system: false },
+  ];
+  const runtime = createRuntime(chat);
+
+  const result = await unhideAll(runtime);
+
+  assert.equal(result.active, false);
+  assert.equal(result.shownCount, 3);
+  assert.deepEqual(runtime.commands, ["/unhide 0-2"]);
+  assert.equal(chat[0].is_system, false);
+  assert.equal(chat[1].is_system, false);
+  assert.equal(chat[0].extra, undefined);
+  assert.equal(chat[1].extra, undefined);
+}
+
 await testApplyUsesNativeHide();
 await testDisableUnhidesManagedRange();
 await testIncrementalOnlyHidesOverflowDelta();
 await testResetClearsStateWithoutIssuingCommands();
+await testUnhideAllRecoversPersistedManagedMarkersAfterStateLoss();
 
 console.log("hide-engine tests passed");
diff --git a/tests/indexeddb-sync.mjs b/tests/indexeddb-sync.mjs
index 97aa965..1073aaf 100644
--- a/tests/indexeddb-sync.mjs
+++ b/tests/indexeddb-sync.mjs
@@ -341,6 +341,49 @@ async function testDownloadImport() {
   assert.equal(db.lastImportPayload.nodes[0].id, "remote-node");
 }
 
+async function testLegacyRemoteFilenameFallbackAndReuse() {
+  const { fetch, remoteFiles, logs } = createMockFetchEnvironment();
+  const dbByChatId = new Map();
+  const chatId = "chat~legacy name";
+  const db = new FakeDb(chatId);
+  dbByChatId.set(chatId, db);
+
+  remoteFiles.set("ST-BME_sync_chat~legacy_name.json", {
+    meta: {
+      schemaVersion: 1,
+      chatId,
+      revision: 4,
+      deviceId: "remote-device",
+      lastModified: 400,
+      nodeCount: 1,
+      edgeCount: 0,
+      tombstoneCount: 0,
+    },
+    nodes: [{ id: "legacy-node", updatedAt: 300 }],
+    edges: [],
+    tombstones: [],
+    state: {
+      lastProcessedFloor: 3,
+      extractionCount: 2,
+    },
+  });
+
+  const runtime = buildRuntimeOptions({ dbByChatId, fetch });
+  const status = await getRemoteStatus(chatId, runtime);
+  assert.equal(status.exists, true);
+  assert.equal(status.filename, "ST-BME_sync_chat~legacy_name.json");
+
+  const downloadResult = await download(chatId, runtime);
+  assert.equal(downloadResult.downloaded, true);
+  assert.equal(downloadResult.filename, "ST-BME_sync_chat~legacy_name.json");
+  assert.equal(db.lastImportPayload.nodes[0].id, "legacy-node");
+
+  const uploadResult = await upload(chatId, runtime);
+  assert.equal(uploadResult.uploaded, true);
+  assert.equal(uploadResult.filename, "ST-BME_sync_chat~legacy_name.json");
+  assert.equal(logs.uploadedPayloads.at(-1)?.name, "ST-BME_sync_chat~legacy_name.json");
+}
+
 async function testMergeRules() {
   const local = {
     meta: {
@@ -595,6 +638,38 @@ async function testDeleteRemoteSyncFile() {
   assert.equal(logs.deleteCalls, 2);
 }
 
+async function testDeleteRemoteSyncFileFallsBackToLegacyFilename() {
+  const { fetch, remoteFiles, logs } = createMockFetchEnvironment();
+  const dbByChatId = new Map();
+  const chatId = "chat~legacy delete";
+  dbByChatId.set(chatId, new FakeDb(chatId));
+  remoteFiles.set("ST-BME_sync_chat~legacy_delete.json", {
+    meta: {
+      schemaVersion: 1,
+      chatId,
+      revision: 1,
+      lastModified: 10,
+      deviceId: "remote-device",
+      nodeCount: 0,
+      edgeCount: 0,
+      tombstoneCount: 0,
+    },
+    nodes: [],
+    edges: [],
+    tombstones: [],
+    state: {
+      lastProcessedFloor: -1,
+      extractionCount: 0,
+    },
+  });
+
+  const runtime = buildRuntimeOptions({ dbByChatId, fetch });
+  const deleteResult = await deleteRemoteSyncFile(chatId, runtime);
+  assert.equal(deleteResult.deleted, true);
+  assert.equal(deleteResult.filename, "ST-BME_sync_chat~legacy_delete.json");
+  assert.equal(logs.deleteCalls, 2, "应先尝试新文件名，再回退删除 legacy 文件名");
+}
+
 async function testAutoSyncOnVisibility() {
   const { fetch, logs } = createMockFetchEnvironment();
   const dbByChatId = new Map();
@@ -748,10 +823,12 @@ async function main() {
   await testUploadPayloadMetaFirstAndDebounce();
   await testUploadSanitizesIllegalChatIdFilename();
   await testDownloadImport();
+  await testLegacyRemoteFilenameFallbackAndReuse();
   await testMergeRules();
   await testMergeRuntimeMetaPolicies();
   await testSyncNowLockAndAutoSync();
   await testDeleteRemoteSyncFile();
+  await testDeleteRemoteSyncFileFallsBackToLegacyFilename();
   await testAutoSyncOnVisibility();
   await testSyncNowRemoteReadErrorPath();
   await testSyncAppliedHook();