diff --git a/src/components/documents/folder-tree-sidebar.tsx b/src/components/documents/folder-tree-sidebar.tsx
index f1e90319..dff1d558 100644
--- a/src/components/documents/folder-tree-sidebar.tsx
+++ b/src/components/documents/folder-tree-sidebar.tsx
@@ -25,12 +25,8 @@ interface FolderTreeSidebarProps {
  * Designed for unlimited depth — only the top level renders by default
  * so deep trees don't blow out the page; reps drill in by expanding.
  */
-export function FolderTreeSidebar({
-  selectedFolderId,
-  onSelect,
-  footer,
-}: FolderTreeSidebarProps) {
-  const { data: tree = [], isLoading } = useDocumentFolders();
+export function FolderTreeSidebar({ selectedFolderId, onSelect, footer }: FolderTreeSidebarProps) {
+  const { data: tree = [], isLoading, isError } = useDocumentFolders();
 
   return (
     <aside className="w-full sm:w-60 shrink-0 border-r bg-muted/40 p-2">
@@ -54,6 +50,8 @@ export function FolderTreeSidebar({
       <div className="mt-3 space-y-0.5">
         {isLoading ? (
           <p className="px-2 text-xs text-muted-foreground">Loading…</p>
+        ) : isError ? (
+          <p className="px-2 text-xs text-destructive">Failed to load folders.</p>
         ) : tree.length === 0 ? (
           <p className="px-2 text-xs text-muted-foreground">No folders yet.</p>
         ) : (