diff --git a/crates/engine/src/optimizer.rs b/crates/engine/src/optimizer.rs
index 68f5a143da..b403b82373 100644
--- a/crates/engine/src/optimizer.rs
+++ b/crates/engine/src/optimizer.rs
@@ -95,12 +95,12 @@ impl OptimizeJob {
         let discarded = if discard.is_empty() {
             Vec::new()
         } else {
-            // `remove_hidden` refuses a run that removes nothing. Ticked categories that hold
-            // nothing are nothing to discard, not a reason to end the whole optimization.
-            match pdfcraft_redact::sanitize::remove_hidden(&mut cos, &discard) {
-                Err(pdfcraft_redact::RedactError::NothingToApply) => Vec::new(),
-                r => r?,
-            }
+            // Only the ticked categories its scan finds something in: `remove_hidden` refuses when
+            // it counts every one it is given as 0, which would end the whole optimization, and
+            // may have changed the copy by then (an empty outline root goes with bookmarks).
+            let counts = pdfcraft_redact::sanitize::scan(&cos);
+            let which: Vec<Hidden> = discard.iter().copied().filter(|h| counts.iter().any(|(c, n)| c == h && *n > 0)).collect();
+            if which.is_empty() { Vec::new() } else { pdfcraft_redact::sanitize::remove_hidden(&mut cos, &which)? }
         };
         let report = optimize::optimize_with_progress(&mut cos, &settings, &mut |s| {
             step(match s {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 18108c44da..9f5dece295 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -3618,6 +3618,21 @@ fn optimize_discarding_an_empty_category_still_runs() {
     let (bytes, report) = s.optimized_bytes(id, &optimize::Settings::default(), &[crate::Hidden::Bookmarks, crate::Hidden::Comments]).unwrap();
     assert!(bytes.starts_with(b"%PDF-"));
     assert!(report.discarded.is_empty(), "{:?}", report.discarded);
+    // An outline root with no entries is no bookmarks: it stays, as Remove Hidden Information,
+    // which refuses then, leaves it.
+    let outline = pdfcraft_testkit::Pdf::new()
+        .obj("<< /Type /Catalog /Pages 2 0 R /Outlines 4 0 R /PageMode /UseOutlines >>")
+        .obj("<< /Type /Pages /Kids [3 0 R] /Count 1 /MediaBox [0 0 612 792] >>")
+        .obj("<< /Type /Page /Parent 2 0 R >>")
+        .obj("<< /Type /Outlines /Count 0 >>")
+        .build();
+    let mut s = Session::new();
+    let id = s.open("outline.pdf", None, Arc::new(outline), None).unwrap();
+    let (bytes, report) = s.optimized_bytes(id, &optimize::Settings::default(), &[crate::Hidden::Bookmarks]).unwrap();
+    assert!(report.discarded.is_empty(), "{:?}", report.discarded);
+    let saved = pdfcraft_cos::Document::open(bytes).unwrap();
+    let catalog = saved.get(saved.root().unwrap()).as_dict().cloned().unwrap();
+    assert!(catalog.contains(b"Outlines") && catalog.contains(b"PageMode"), "{catalog:?}");
 }
 
 #[test]