diff --git a/js/app/authSessionCoordinator.js b/js/app/authSessionCoordinator.js
index 19541530..1fffe76f 100644
--- a/js/app/authSessionCoordinator.js
+++ b/js/app/authSessionCoordinator.js
@@ -618,31 +618,19 @@ export function createAuthSessionCoordinator(deps) {
         return listSyncDetail;
       });
 
-      // DMs can wait for profile since they need encryption context.
+      // DMs are intentionally NOT eagerly loaded at login. A cold DM load
+      // (limit: 50) is a burst of nip-07 decrypts that competes with the
+      // feed-driving lists (blocks/subscriptions/hashtags) for the SAME
+      // single-threaded extension channel during the fragile post-login
+      // handshake window — under load that channel drops ("message channel
+      // closed") and every subsequent decrypt times out until a page refresh.
+      // DMs are lower priority (the user isn't viewing Messages at login) and
+      // already load lazily when the Messages tab is opened
+      // (ProfileDirectMessageActions.populateProfileMessages). The lightweight
+      // unread indicator (refreshUnreadDmIndicator, above) still runs so the
+      // badge is accurate without decrypting the full conversation history.
       const dmStatePromise = profileStatePromise.then(() => {
-        if (
-          activePubkey &&
-          this.nostrService &&
-          typeof this.nostrService.loadDirectMessages === "function"
-        ) {
-          return this.nostrService
-            .loadDirectMessages({
-              actorPubkey: activePubkey,
-              limit: 50,
-              initialLoad: true,
-            })
-            .then(() => {
-              this.updateAuthLoadingState({ dms: "ready" });
-            })
-            .catch((error) => {
-              devLogger.warn(
-                "[Application] Failed to load direct messages during login:",
-                error,
-              );
-              this.updateAuthLoadingState({ dms: "error" });
-            });
-        }
-        this.updateAuthLoadingState({ dms: "idle" });
+        this.updateAuthLoadingState({ dms: "deferred" });
         return Promise.resolve();
       });
 
diff --git a/tests/app/login-defers-dms.test.mjs b/tests/app/login-defers-dms.test.mjs
new file mode 100644
index 00000000..95f3b649
--- /dev/null
+++ b/tests/app/login-defers-dms.test.mjs
@@ -0,0 +1,143 @@
+// Scenario (SCN-login-defers-dms):
+//   Given a user logs in via the auth session coordinator,
+//   When the post-login hydration runs (profile + feed-driving lists settle),
+//   Then the coordinator MUST NOT eagerly load the full direct-message history
+//     (a cold limit:50 DM load is a burst of nip-07 decrypts that competes with
+//     blocks/subscriptions/hashtags for the single-threaded extension channel
+//     during the fragile handshake window — see KNOWN_BUGS #0). DMs load lazily
+//     when the Messages tab is opened instead.
+//   And the DM loading state is reported as "deferred" (not "ready"/"loading"),
+//   And the lightweight unread indicator still runs so the badge stays accurate.
+
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+// Minimal browser shim: handleAuthLogin reads window.location.search.
+if (typeof globalThis.window === "undefined") {
+  globalThis.window = { location: { search: "", href: "http://localhost/" } };
+}
+
+const { createAuthSessionCoordinator } = await import(
+  "../../js/app/authSessionCoordinator.js"
+);
+
+const ACTIVE_PUBKEY = "a".repeat(64);
+
+function makeCoordinator({ loadDirectMessages, refreshUnreadDmIndicator }) {
+  const noop = () => {};
+  const asyncNoop = async () => {};
+  const logger = { warn: noop, info: noop, log: noop, error: noop, debug: noop };
+
+  const coord = createAuthSessionCoordinator({
+    devLogger: logger,
+    userLogger: logger,
+    nostrClient: {
+      // Signer resolves so the readiness gate completes (non-extension type so
+      // it doesn't attempt a real permission prompt).
+      ensureActiveSignerForPubkey: async () => ({ type: "nsec", pubkey: ACTIVE_PUBKEY }),
+      ensureExtensionPermissions: async () => ({ ok: true }),
+    },
+    accessControl: { ensureReady: asyncNoop, getBlacklist: () => [] },
+    userBlocks: {
+      getBlockedPubkeys: () => [],
+      seedWithNpubs: asyncNoop,
+    },
+    subscriptions: { ensureLoaded: asyncNoop, lastLoadError: null },
+    hashtagPreferences: { load: asyncNoop, lastLoadError: null },
+    storageService: {},
+    relayManager: {},
+    torrentClient: {},
+    getHashViewName: () => "",
+    setHashView: noop,
+    DEFAULT_NIP07_PERMISSION_METHODS: [],
+    RELAY_UI_BATCH_DELAY_MS: 0,
+    sanitizeRelayList: (x) => x,
+    buildDmRelayListEvent: noop,
+    publishEventToRelays: noop,
+    assertAnyRelayAccepted: noop,
+    queueSignEvent: noop,
+    bootstrapTrustedSeeds: noop,
+    getModerationSettings: () => ({}),
+    getActiveProfilePubkey: () => null,
+  });
+
+  // Collaborators the login flow touches on `this` — stub as inert so the flow
+  // runs end to end without real UI/services.
+  coord.pubkey = ACTIVE_PUBKEY;
+  coord.profileController = null;
+  coord.commentController = null;
+  coord.nwcSettingsService = null;
+  coord.authService = {
+    loadBlocksForPubkey: async () => true,
+  };
+  coord.nostrService = {
+    loadDirectMessages,
+    listDirectMessageConversationSummaries: async () => [],
+  };
+
+  const inert = [
+    "applyAuthenticatedUiState",
+    "capturePermissionPromptFromError",
+    "dispatchAuthChange",
+    "forceRefreshAllProfiles",
+    "maybeShowExperimentalLoginWarning",
+    "reinitializeVideoListView",
+    "renderSavedProfiles",
+    "refreshAllVideoGrids",
+    "resetPermissionPromptState",
+    "resetViewLoggingState",
+    "updateActiveProfileUI",
+    "updateCachedHashtagPreferences",
+    "updateShareNostrAuthState",
+  ];
+  for (const name of inert) {
+    coord[name] = noop;
+  }
+  coord.normalizeHexPubkey = (x) => x;
+  coord.refreshUnreadDmIndicator = refreshUnreadDmIndicator;
+  coord.updateAuthLoadingState = (patch) => {
+    coord.authLoadingState = { ...(coord.authLoadingState || {}), ...patch };
+  };
+  coord.authLoadingState = { profile: "idle", lists: "idle", dms: "idle" };
+
+  return coord;
+}
+
+test("login does not eagerly load DM history; it is deferred", async () => {
+  let loadDmCalls = 0;
+  let unreadIndicatorCalls = 0;
+  const coord = makeCoordinator({
+    loadDirectMessages: async () => {
+      loadDmCalls += 1;
+      return { ok: true };
+    },
+    refreshUnreadDmIndicator: async () => {
+      unreadIndicatorCalls += 1;
+    },
+  });
+
+  await coord.handleAuthLogin({
+    pubkey: ACTIVE_PUBKEY,
+    identityChanged: true,
+    postLogin: { profile: { name: "tester" } },
+    postLoginPromise: Promise.resolve({ profile: { name: "tester" } }),
+  });
+
+  // Let every post-login promise chain (profile -> dm/nwc, feed sync) settle.
+  await new Promise((resolve) => setTimeout(resolve, 50));
+
+  assert.equal(
+    loadDmCalls,
+    0,
+    "login must NOT eagerly load DM history (it competes with feed lists for the nip-07 channel)",
+  );
+  assert.equal(
+    coord.authLoadingState.dms,
+    "deferred",
+    "DM loading state should be reported as deferred at login",
+  );
+  assert.ok(
+    unreadIndicatorCalls >= 1,
+    "the lightweight unread DM indicator should still run so the badge stays accurate",
+  );
+});