diff --git a/src/main.js b/src/main.js
index 6f88918..9e50cec 100644
--- a/src/main.js
+++ b/src/main.js
@@ -35,113 +35,128 @@ function findAnchorElement() {
 }
 
 function start() {
-  const store = new Store({
-    storage: localStorage,
-    onWarn: (m) => console.warn(m),
-  });
-  const prefs = store.getPrefs();
+  try {
+    const store = new Store({
+      storage: localStorage,
+      onWarn: (m) => console.warn(m),
+    });
+    const prefs = store.getPrefs();
 
-  const dialog = new Dialog({
-    onTargetChange: (v) => {
-      const attr = currentAttribute()?.attr;
-      if (!attr) return;
-      store.setTarget(attr, v);
-      render();
-    },
-    onModeChange: (m) => {
-      store.setMode(m);
-      prefs.mode = m;
-      applyMode();
-    },
-    onPosChange: (pos) => store.setPos(pos),
-    onClose: () => dialog.destroy(),
-  });
+    // State that applyMode() and render() may touch on first call.
+    // Declared up-front to avoid TDZ ReferenceError if applyMode()'s
+    // anchor-miss branch fires before the natural declaration point.
+    let lastSnapshot = null;
+    let lastAttr = null;
+    let lastDelta = 0;
+    let anchorError = null;
 
-  dialog.mount({ initialMode: prefs.mode, initialPos: prefs.pos });
-  applyMode();
-
-  let lastSnapshot = null;
-  let lastAttr = null;
-  let lastDelta = 0;
-  let anchorError = null;
-
-  function snapshot() {
-    const a = currentAttribute();
-    if (!a) {
-      return { error: "Couldn't read attribute — Torn may have updated the page." };
+    // One-time migration: dialog now defaults to bottom-left, so reset any
+    // previously-saved position from the bottom-right era.
+    if (prefs.pos && (prefs.pos.x !== 0 || prefs.pos.y !== 0)) {
+      console.info('[tat] resetting dialog position to new bottom-left default');
+      prefs.pos = { x: 0, y: 0 };
+      store.setPos(prefs.pos);
     }
-    lastAttr = a.attr;
-    const summary = store.getSummary(a.attr);
-    return {
-      attr: a.attr,
-      gym: a.gym,
-      current: a.current,
-      target: store.getTarget(a.attr),
-      perTrain: lastDelta,
-      summary,
-      warn: store._saveDisabled ? 'saving disabled this session' : null,
-      anchorError: anchorError,
-    };
-  }
 
-  function render() {
-    lastSnapshot = snapshot();
-    dialog.render(lastSnapshot);
-  }
+    const dialog = new Dialog({
+      onTargetChange: (v) => {
+        const attr = currentAttribute()?.attr;
+        if (!attr) return;
+        store.setTarget(attr, v);
+        render();
+      },
+      onModeChange: (m) => {
+        store.setMode(m);
+        prefs.mode = m;
+        applyMode();
+      },
+      onPosChange: (pos) => store.setPos(pos),
+      onClose: () => dialog.destroy(),
+    });
 
-  function applyMode() {
-    if (prefs.mode === 'anchored') {
-      const el = findAnchorElement();
-      if (el) {
-        const rect = el.getBoundingClientRect();
-        dialog.setMode('anchored', { canAnchor: true });
-        dialog._positionAnchored(rect);
-        // observe
-        const ro = new ResizeObserver(() => {
-          if (prefs.mode === 'anchored') dialog._positionAnchored(el.getBoundingClientRect());
-        });
-        ro.observe(el);
-        anchorError = null;
+    dialog.mount({ initialMode: prefs.mode, initialPos: prefs.pos });
+    applyMode();
+
+    function snapshot() {
+      const a = currentAttribute();
+      if (!a) {
+        return { error: "Couldn't read attribute — Torn may have updated the page." };
+      }
+      lastAttr = a.attr;
+      const summary = store.getSummary(a.attr);
+      return {
+        attr: a.attr,
+        gym: a.gym,
+        current: a.current,
+        target: store.getTarget(a.attr),
+        perTrain: lastDelta,
+        summary,
+        warn: store._saveDisabled ? 'saving disabled this session' : null,
+        anchorError: anchorError,
+      };
+    }
+
+    function render() {
+      lastSnapshot = snapshot();
+      dialog.render(lastSnapshot);
+    }
+
+    function applyMode() {
+      if (prefs.mode === 'anchored') {
+        const el = findAnchorElement();
+        if (el) {
+          const rect = el.getBoundingClientRect();
+          dialog.setMode('anchored', { canAnchor: true });
+          dialog._positionAnchored(rect);
+          // observe
+          const ro = new ResizeObserver(() => {
+            if (prefs.mode === 'anchored') dialog._positionAnchored(el.getBoundingClientRect());
+          });
+          ro.observe(el);
+          anchorError = null;
+          return;
+        }
+        // Anchor selector missed — don't snap to default, just keep current
+        // position and show a note.
+        anchorError = "Couldn't find the training form on this page.";
+        render();
         return;
       }
-      // Anchor selector missed — don't snap to default, just keep current
-      // position and show a note.
-      anchorError = "Couldn't find the training form on this page.";
-      render();
-      return;
+      anchorError = null;
+      dialog.setMode('free');
     }
-    anchorError = null;
-    dialog.setMode('free');
-  }
 
-  // initial paint
-  render();
+    // initial paint
+    render();
 
-  // watch DOM for attribute changes
-  let pending = false;
-  const observer = new MutationObserver(() => {
-    if (pending) return;
-    pending = true;
-    requestAnimationFrame(() => {
-      pending = false;
-      const a = currentAttribute();
-      if (a && (a.attr !== lastAttr || a.current !== lastSnapshot?.current)) render();
+    // watch DOM for attribute changes
+    let pending = false;
+    const observer = new MutationObserver(() => {
+      if (pending) return;
+      pending = true;
+      requestAnimationFrame(() => {
+        pending = false;
+        const a = currentAttribute();
+        if (a && (a.attr !== lastAttr || a.current !== lastSnapshot?.current)) render();
+      });
     });
-  });
-  observer.observe(document.body, { childList: true, subtree: true, characterData: true });
+    observer.observe(document.body, { childList: true, subtree: true, characterData: true });
 
-  // intercept train requests
-  const prev = currentAttribute()?.current ?? 0;
-  startRequestInterceptor({
-    prevValue: prev,
-    currentAttr: lastAttr,
-    onTrain: ({ attr, delta, ts }) => {
-      store.recordTrain(attr, delta, ts);
-      lastDelta = delta;
-      render();
-    },
-    onParseFail: (url) => console.warn('[tat] could not parse train response from', url),
-  });
+    // intercept train requests
+    const prev = currentAttribute()?.current ?? 0;
+    startRequestInterceptor({
+      prevValue: prev,
+      currentAttr: lastAttr,
+      onTrain: ({ attr, delta, ts }) => {
+        store.recordTrain(attr, delta, ts);
+        lastDelta = delta;
+        render();
+      },
+      onParseFail: (url) => console.warn('[tat] could not parse train response from', url),
+    });
+  } catch (e) {
+    console.error('[tat] failed to start:', e);
+  }
 }
 
 if (location.hash === '#tat-test') {