diff --git a/crates/engine/src/autosave.rs b/crates/engine/src/autosave.rs
index c6b41cce4..9ff7eab0b 100644
--- a/crates/engine/src/autosave.rs
+++ b/crates/engine/src/autosave.rs
@@ -416,6 +416,13 @@ mod native {
             writes
         }
 
+        /// Whether a background write hasn't finished yet. Its file can exist before it finishes
+        /// (the folder is synced after the rename), and until [`Autosaver::reap`] takes it in, the
+        /// drawing is left out of planning.
+        pub fn writing(&self) -> bool {
+            self.running.iter().any(|(_, h)| !h.is_finished())
+        }
+
         /// Take in the writes that have finished ([`Autosaver::tick`] does this first). A drawing
         /// whose write failed is no longer counted as autosaved: the next plan restarts its clock,
         /// so it is tried again SAVETIME later even if it doesn't change.
diff --git a/crates/engine/tests/autosave.rs b/crates/engine/tests/autosave.rs
index da03c0d7d..f44be5231 100644
--- a/crates/engine/tests/autosave.rs
+++ b/crates/engine/tests/autosave.rs
@@ -185,6 +185,14 @@ fn autosave_files_are_written_in_the_background_and_removed_on_exit() {
         std::thread::sleep(Duration::from_millis(10));
     }
     assert!(std::fs::read(&path).unwrap().ends_with(b"EOF\n"));
+    // The file exists before the write finishes (the folder sync comes after the rename); until
+    // it has, the drawing is busy and the change drawn below would not be planned.
+    for _ in 0..500 {
+        if !a.writing() {
+            break;
+        }
+        std::thread::sleep(Duration::from_millis(10));
+    }
     // While the app runs, its lock keeps its files out of recovery. SAVETIME and SAVEFILEPATH
     // are system variables (process-wide, so set in this test only).
     assert_eq!(cadcraft_engine::sysvars::get(&s, "SAVETIME"), Some(json!(10)));