diff --git a/crates/engine/src/cmd/fileio/mod.rs b/crates/engine/src/cmd/fileio/mod.rs
index 2fb4cec00..4b05cb8ab 100644
--- a/crates/engine/src/cmd/fileio/mod.rs
+++ b/crates/engine/src/cmd/fileio/mod.rs
@@ -74,7 +74,7 @@ pub use native::with_compression_pref;
 pub use pdfimport::{LoadOptions, page_document};
 pub(crate) use save::job_for;
 pub use save::{
-    SAVE_FORMATS, SaveJob, SaveMode, SavePlan, StreamWrite, TEMPLATE_FORMATS, export_folder, reads_option as save_reads_option,
+    SAVE_FORMATS, SaveJob, SaveMode, SavePlan, StreamWrite, TEMPLATE_FORMATS, dialog_folder, export_folder, reads_option as save_reads_option,
     remembered_save_options, save_filters, save_format, save_job, save_plan, save_with, stamp_save_dates, template_filters, templates_dialog_folder,
     templates_folder,
 };
diff --git a/crates/engine/src/cmd/fileio/save.rs b/crates/engine/src/cmd/fileio/save.rs
index 1d70e99f2..486777a24 100644
--- a/crates/engine/src/cmd/fileio/save.rs
+++ b/crates/engine/src/cmd/fileio/save.rs
@@ -185,6 +185,14 @@ fn parent_folder(path: &str) -> Option<String> {
     std::path::Path::new(path).parent().map(|p| p.to_string_lossy().to_string()).filter(|p| !p.is_empty())
 }
 
+/// A file dialog's starting folder for a path on disk (#4122): the path's parent when it is a
+/// folder, else the nearest ancestor directory that exists.
+pub fn dialog_folder(path: &str) -> Option<String> {
+    let folder = parent_folder(path)?;
+    let path = std::path::PathBuf::from(folder);
+    path.ancestors().find(|a| a.is_dir()).map(|a| a.to_string_lossy().into_owned())
+}
+
 /// A save format by id or extension, or why it isn't one.
 fn save_format_of(f: &str) -> std::result::Result<&'static Format, String> {
     match format(f) {
@@ -300,7 +308,7 @@ fn disagreeing_option(p: &Value, svg: bool) -> std::result::Result<Option<(Strin
             .as_object()
             .into_iter()
             .flatten()
-            .filter(|(k, v)| !(v.is_null() || matches!(k.as_str(), "path" | "format" | "options") || (svg && k.as_str() == "svg")))
+            .filter(|(k, v)| !(v.is_null() || matches!(k.as_str(), "path" | "format" | "options") || svg && k.as_str() == "svg"))
             .map(|(k, v)| (k.clone(), v.clone()))
             .collect();
         if svg {
@@ -1020,6 +1028,20 @@ mod tests_folders {
         assert_eq!(super::xdg_documents("XDG_MUSIC_DIR=\"$HOME/Musica\"", home), None);
     }
 
+    /// #4122: File → Open starts in the folder of the last opened file.
+    #[test]
+    fn dialog_folder_is_the_nearest_existing_parent() {
+        let base = std::env::temp_dir().join(format!("vc-open-folder-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&base);
+        std::fs::create_dir_all(&base).unwrap();
+        let file = base.join("poster.svg");
+        assert_eq!(super::dialog_folder(&file.to_string_lossy()).map(PathBuf::from), Some(base.clone()));
+        let missing = base.join("gone").join("card.ai");
+        assert_eq!(super::dialog_folder(&missing.to_string_lossy()).map(PathBuf::from), Some(base.clone()));
+        assert!(super::dialog_folder("poster.svg").is_none());
+        let _ = std::fs::remove_dir_all(&base);
+    }
+
     /// #703: the Templates folder a dialog starts in exists: made when missing, else the nearest
     /// folder above it.
     #[test]
diff --git a/crates/ui-egui/src/io.rs b/crates/ui-egui/src/io.rs
index 90078a677..43c5b1746 100644
--- a/crates/ui-egui/src/io.rs
+++ b/crates/ui-egui/src/io.rs
@@ -189,13 +189,20 @@ pub fn install_module(app: &mut VectorcraftApp, module: Value) -> Result<Value,
     Ok(r)
 }
 
+/// Where File → Open… starts: the folder of the most recently opened file, else the active
+/// document's (#4122).
+fn open_dialog_folder(app: &VectorcraftApp) -> Option<String> {
+    app.ui.recent_files.iter().find_map(|p| fileio::dialog_folder(p)).or_else(|| suggested(app, "").1)
+}
+
 /// File → Open…
 pub fn open_dialog(app: &mut VectorcraftApp) -> Result<(), String> {
     if let Some(f) = app.services.open_async.as_mut() {
         f();
         return Ok(());
     }
-    let path = pick_open(app, &FilePick { filters: FilePick::filters(fileio::open_filters()), ..Default::default() })?;
+    let path =
+        pick_open(app, &FilePick { filters: FilePick::filters(fileio::open_filters()), folder: open_dialog_folder(app), ..Default::default() })?;
     open_reporting(app, &path).map(|_| ())
 }
 
diff --git a/crates/ui-egui/src/tests_picks.rs b/crates/ui-egui/src/tests_picks.rs
index ece5aa444..686fddd18 100644
--- a/crates/ui-egui/src/tests_picks.rs
+++ b/crates/ui-egui/src/tests_picks.rs
@@ -154,12 +154,28 @@ fn saved_document(app: &mut VectorcraftApp, tag: &str) -> (std::path::PathBuf, S
 
 // ------------------------------------------------------------------------------------- the tests
 
+#[test]
+fn file_open_starts_in_the_last_opened_files_folder() {
+    let (mut app, shown, _) = app();
+    let dir = std::env::temp_dir().join(format!("vc-open-dialog-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("poster.svg").to_string_lossy().into_owned();
+    crate::io::note_recent(&mut app, &path);
+    assert!(app.run("file.open", json!({})).is_err());
+    poll(&mut app);
+    let folder = dir.to_string_lossy().into_owned();
+    assert!(matches!(shown.requests().as_slice(), [PickRequest::Open(p)] if p.folder == Some(folder)));
+    shown.answer(&[]);
+    poll(&mut app);
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
 #[test]
 fn file_open_opens_what_its_dialog_picks_when_it_answers() {
     let (mut app, shown, _) = app();
     // The dialog shows; File › Open gives up for now, without a "cancelled".
     assert!(app.run("file.open", json!({})).is_err());
-    assert!(matches!(shown.requests().as_slice(), [PickRequest::Open(_)]));
+    assert!(matches!(shown.requests().as_slice(), [PickRequest::Open(p)] if p.folder.is_none()));
     poll(&mut app);
     assert!(app.session.documents().is_empty() && app.ui.status.is_empty(), "{}", app.ui.status);
     // Another dialog waits for this one.