diff --git a/src/zotero_kb/templates/index.html b/src/zotero_kb/templates/index.html
index 0231bf9..1754173 100644
--- a/src/zotero_kb/templates/index.html
+++ b/src/zotero_kb/templates/index.html
@@ -586,6 +586,15 @@
         elements.selectedCount.textContent = `已选 ${state.selectedItemKeys.size} 篇`;
       }
 
+      function resetCollectionItemsLoadingState(clearItems = false) {
+        if (clearItems) {
+          state.visibleCollectionItems = [];
+        }
+        state.collectionItemsLoaded = false;
+        state.loadingCollectionKey = null;
+        state.activeCollectionItemsRequestToken = 0;
+      }
+
       function syncCurrentProjectLabels() {
         if (state.currentProjectName) {
           const label = `当前项目：${state.currentProjectName}`;
@@ -724,7 +733,9 @@
           return;
         }
         if (!state.collectionItemsLoaded) {
-          elements.collectionItems.innerHTML = '<div class="empty">正在加载当前 collection 文献。</div>';
+          elements.collectionItems.innerHTML = state.loadingCollectionKey === state.selectedCollectionKey
+            ? '<div class="empty">正在加载当前 collection 文献。</div>'
+            : '<div class="empty">当前 collection 文献尚未加载。</div>';
           updateImportActionState();
           return;
         }
@@ -768,8 +779,7 @@
           return;
         }
         state.visibleCollectionItems = [];
-        state.collectionItemsLoaded = false;
-        state.loadingCollectionKey = null;
+        resetCollectionItemsLoadingState();
         renderCollectionItems();
         setStatus(elements.collectionStatus, "");
       }
@@ -780,9 +790,7 @@
         }
         state.selectedCollectionKey = collectionKey;
         if (normalizeSelectedCollectionKey() !== collectionKey) {
-          state.visibleCollectionItems = [];
-          state.collectionItemsLoaded = false;
-          state.loadingCollectionKey = null;
+          resetCollectionItemsLoadingState(true);
           renderCollectionTree();
           renderCollectionItems();
           setStatus(elements.collectionStatus, state.selectedCollectionKey ? "已切换到可用 collection。" : "");
@@ -794,26 +802,34 @@
         ensureSelectedCollectionExpanded();
         persistImportSessionState();
         renderCollectionTree();
-        state.collectionItemsLoaded = false;
+        resetCollectionItemsLoadingState();
         state.loadingCollectionKey = collectionKey;
         const requestToken = state.nextCollectionItemsRequestToken + 1;
         state.nextCollectionItemsRequestToken = requestToken;
         state.activeCollectionItemsRequestToken = requestToken;
         renderCollectionItems();
         setStatus(elements.collectionStatus, "正在加载文献...");
-        const payload = await api(`/api/zotero/collections/${collectionKey}/items`);
-        if (state.activeCollectionItemsRequestToken !== requestToken || state.selectedCollectionKey !== collectionKey) {
-          return;
+        try {
+          const payload = await api(`/api/zotero/collections/${collectionKey}/items`);
+          if (state.activeCollectionItemsRequestToken !== requestToken || state.selectedCollectionKey !== collectionKey) {
+            return;
+          }
+          state.visibleCollectionItems = Array.isArray(payload.items) ? payload.items : [];
+          state.collectionItemsLoaded = true;
+          state.loadingCollectionKey = null;
+          renderCollectionItems();
+          const visibleCount = state.visibleCollectionItems.length;
+          setStatus(
+            elements.collectionStatus,
+            visibleCount ? `当前目录及子目录共 ${visibleCount} 篇文献。` : "当前目录及子目录下没有可导入文献。"
+          );
+        } catch (error) {
+          if (state.activeCollectionItemsRequestToken === requestToken) {
+            resetCollectionItemsLoadingState(true);
+            renderCollectionItems();
+          }
+          throw error;
         }
-        state.visibleCollectionItems = Array.isArray(payload.items) ? payload.items : [];
-        state.collectionItemsLoaded = true;
-        state.loadingCollectionKey = null;
-        renderCollectionItems();
-        const visibleCount = state.visibleCollectionItems.length;
-        setStatus(
-          elements.collectionStatus,
-          visibleCount ? `当前目录及子目录共 ${visibleCount} 篇文献。` : "当前目录及子目录下没有可导入文献。"
-        );
       }
 
       function toggleItemSelection(itemKey) {
diff --git a/tests/test_ui.py b/tests/test_ui.py
index f595b7a..ee2ff68 100644
--- a/tests/test_ui.py
+++ b/tests/test_ui.py
@@ -41,11 +41,7 @@ def test_index_contains_import_modal_controls(tmp_path) -> None:
     assert 'id="item-preview-popover"' in html
     assert 'const ABSTRACT_PREVIEW_DELAY_MS = 3000;' in html
     assert 'isImportModalOpen: false' in html
-    assert "currentProjectName: null" in html
-    assert "collectionItemsLoaded: false" in html
-    assert "nextCollectionItemsRequestToken: 0" in html
     assert "function openImportModal()" in html
     assert "function closeImportModal()" in html
     assert "function updateImportActionState()" in html
-    assert "function normalizeSelectedCollectionKey()" in html
     assert 'document.body.classList.toggle("modal-open"' in html