diff --git a/crates/engine/src/cmd/swatchlib.rs b/crates/engine/src/cmd/swatchlib.rs
index f5d4b74a1..98e3272d0 100644
--- a/crates/engine/src/cmd/swatchlib.rs
+++ b/crates/engine/src/cmd/swatchlib.rs
@@ -152,13 +152,16 @@ impl<L: LibraryFile> Libraries<L> {
     }
 
     /// Re-read the library files of the user library folder (unreadable ones are skipped). The
-    /// folder is the app's own: automation roots don't apply to it ([`crate::file_access`]).
+    /// folder is the app's own: automation roots don't apply to it ([`crate::file_access`]). Each
+    /// file is read inside [`crate::guard::catch_panic`], and a file whose reading panics is
+    /// skipped too.
     pub fn rescan(&mut self) {
         self.extra.retain(|e| e.info.category != "user");
         let Some(dir) = self.user_dir.clone() else { return };
         for path in library_files(&dir, L::EXTS) {
             let file = file_name(&path);
-            let Some(lib) = crate::file_access::unconfined(|| read_file(&path)).ok().and_then(|b| L::read(&b, stem(&file)).ok()) else { continue };
+            let read = || crate::file_access::unconfined(|| read_file(&path)).ok().and_then(|b| L::read(&b, stem(&file)).ok());
+            let Some(lib) = crate::guard::catch_panic(read).ok().flatten() else { continue };
             let info = LibraryInfo { id: format!("user/{file}"), name: lib.name().to_string(), category: "user" };
             self.extra.push(Extra { info, path: Some(path), lib: Arc::new(lib) });
         }
diff --git a/crates/engine/src/tests_swatchlib.rs b/crates/engine/src/tests_swatchlib.rs
index 0f25a04ec..6be4e4f5a 100644
--- a/crates/engine/src/tests_swatchlib.rs
+++ b/crates/engine/src/tests_swatchlib.rs
@@ -189,6 +189,38 @@ fn libraries_saved_in_the_user_folder_are_user_defined() {
     let _ = std::fs::remove_dir_all(dir);
 }
 
+/// A library kind whose reader panics on a file that holds `trap`, as a parser bug would.
+#[derive(Default)]
+struct Trap(String);
+
+impl cmd::swatchlib::LibraryFile for Trap {
+    const EXTS: &'static [&'static str] = &["trap"];
+    fn read(bytes: &[u8], stem: &str) -> std::result::Result<Self, String> {
+        if bytes == b"trap" {
+            panic!("a parser bug");
+        }
+        Ok(Self(stem.to_string()))
+    }
+    fn name(&self) -> &str {
+        &self.0
+    }
+}
+
+/// When reading one file of the user library folder panics, `set_user_dir` (as the desktop app
+/// calls it at launch) skips that file and lists the other one.
+#[test]
+fn a_user_library_file_whose_reading_panics_is_skipped() {
+    let dir = temp_dir("user-panic");
+    std::fs::create_dir_all(&dir).unwrap();
+    std::fs::write(dir.join("Calm.trap"), "calm").unwrap();
+    std::fs::write(dir.join("Loud.trap"), "trap").unwrap();
+    let mut libraries = cmd::swatchlib::Libraries::<Trap>::default();
+    libraries.set_user_dir(Some(dir.to_string_lossy().to_string()));
+    let names: Vec<&str> = libraries.infos().map(|l| l.name.as_str()).collect();
+    assert_eq!(names, ["Calm"]);
+    let _ = std::fs::remove_dir_all(dir);
+}
+
 #[test]
 fn another_documents_swatches_load_as_a_library() {
     let mut s = session();