diff --git a/apps/desktop/src/components/grid/DataGrid.vue b/apps/desktop/src/components/grid/DataGrid.vue
index 4bb52f469f..5733f1c5ca 100644
--- a/apps/desktop/src/components/grid/DataGrid.vue
+++ b/apps/desktop/src/components/grid/DataGrid.vue
@@ -364,14 +364,14 @@ const DataGridInsertRowsDialog = defineAsyncComponent(() => import("@/components
 const ExportProgressDialog = defineAsyncComponent(() => import("@/components/export/ExportProgressDialog.vue"));
 const FORMATTED_JSON_EDIT_WARNING_COUNT_STORAGE_KEY = "dbx-cell-detail-formatted-json-edit-warning-count";
 const FORMATTED_JSON_EDIT_WARNING_MAX_COUNT = 3;
-let largeValueRuntime: ReturnType<typeof useDataGridLargeValues>;
+let largeValueRuntime: ReturnType<typeof useDataGridLargeValues> | undefined;
 
 function scheduleVisibleLargeValuePreviewHydration(delay = 150) {
-  largeValueRuntime.scheduleVisibleLargeValuePreviewHydration(delay);
+  largeValueRuntime?.scheduleVisibleLargeValuePreviewHydration(delay);
 }
 
 async function hydrateLargeValueCell(rowId: number, columnIndex: number): Promise<boolean> {
-  return largeValueRuntime.hydrateLargeValueCell(rowId, columnIndex);
+  return largeValueRuntime?.hydrateLargeValueCell(rowId, columnIndex) ?? false;
 }
 
 const { t } = useI18n();
@@ -3503,7 +3503,7 @@ const editor = useDataGridEditor({
   cacheKey: computed(() => props.pendingStateKey ?? props.cacheKey),
   onResultPayloadMutated: () => queryStore.invalidateResultEstimateForPayload(props.result),
   refreshSavedRows,
-  onCellValueChanged: (rowId, columnIndex) => largeValueRuntime.invalidateVisibleLargeValuePreviewCell(rowId, columnIndex),
+  onCellValueChanged: (rowId, columnIndex) => largeValueRuntime?.invalidateVisibleLargeValuePreviewCell(rowId, columnIndex),
   prepareFullReload,
   emit,
 });
diff --git a/apps/desktop/src/components/grid/__tests__/DataGridInitializationOrder.spec.ts b/apps/desktop/src/components/grid/__tests__/DataGridInitializationOrder.spec.ts
index 0a0d701154..3cde354a5b 100644
--- a/apps/desktop/src/components/grid/__tests__/DataGridInitializationOrder.spec.ts
+++ b/apps/desktop/src/components/grid/__tests__/DataGridInitializationOrder.spec.ts
@@ -21,4 +21,10 @@ describe("DataGrid setup initialization order", () => {
     expect(filterPreviewDeclaration).toBeGreaterThan(canUseWhereSearchDeclaration);
     expect(filterPreviewWatcher).toBeGreaterThan(filterPreviewDeclaration);
   });
+
+  it("does not expose an uninitialized large-value runtime to startup callbacks", () => {
+    expect(dataGridSource).toContain("let largeValueRuntime: ReturnType<typeof useDataGridLargeValues> | undefined;");
+    expect(dataGridSource).toContain("largeValueRuntime?.scheduleVisibleLargeValuePreviewHydration(delay)");
+    expect(dataGridSource).toContain("largeValueRuntime?.hydrateLargeValueCell(rowId, columnIndex) ?? false");
+  });
 });
diff --git a/apps/desktop/src/composables/useDataGridColumnResize.ts b/apps/desktop/src/composables/useDataGridColumnResize.ts
index 9a153a6be2..295acbc98a 100644
--- a/apps/desktop/src/composables/useDataGridColumnResize.ts
+++ b/apps/desktop/src/composables/useDataGridColumnResize.ts
@@ -86,7 +86,7 @@ export function useDataGridColumnResize(options: UseDataGridColumnResizeOptions)
     });
   }
 
-  const neededColumnWidths = computed(() => columns.value.map((_, colIdx) => neededColumnWidth(colIdx)));
+  const neededColumnWidths = computed(() => (columns.value ?? []).map((_, colIdx) => neededColumnWidth(colIdx)));
   const neededColumnWidthSignature = computed(() => neededColumnWidths.value.join("|"));
 
   /** Grow-only: late pages with larger keys must not stay stuck at a short-header / early-page width. */
@@ -123,9 +123,10 @@ export function useDataGridColumnResize(options: UseDataGridColumnResizeOptions)
     const nextColumnIndexes = [...columnIndexes.value];
     const cachedState = !force && previousColumnIndexes.length === 0 ? loadDataGridColumnWidthState(columnWidthStateIdentity(), nextColumnIndexes) : undefined;
     if (cachedState) userSizedColumnIndexes = new Set(cachedState.userSizedColumnIndexes);
-    const currentNeededWidths = neededColumnWidths.value;
-    if (force || columnWidths.value.length !== columns.value.length || previousColumnIndexes.join("\0") !== nextColumnIndexes.join("\0")) {
-      columnWidths.value = columns.value.map((_, colIdx) => {
+    const currentNeededWidths = neededColumnWidths.value ?? [];
+    const columnCount = columns.value?.length ?? 0;
+    if (force || columnWidths.value.length !== columnCount || previousColumnIndexes.join("\0") !== nextColumnIndexes.join("\0")) {
+      columnWidths.value = (columns.value ?? []).map((_, colIdx) => {
         if (!force) {
           const existingWidth = previousWidthsByColumnIndex.get(nextColumnIndexes[colIdx]);
           if (existingWidth !== undefined) return existingWidth;