diff --git a/l4d2web/l4d2web/static/js/files-overlay/editor.js b/l4d2web/l4d2web/static/js/files-overlay/editor.js
index 03a3384..320a9c8 100644
--- a/l4d2web/l4d2web/static/js/files-overlay/editor.js
+++ b/l4d2web/l4d2web/static/js/files-overlay/editor.js
@@ -181,7 +181,10 @@
       : ta.value;
 
     // is_new mode: relPath is empty; compose path from data-at-folder
-    // + filename. The /save endpoint creates the file when missing.
+    // + filename. The /save endpoint creates the file when missing,
+    // 409s when the destination already exists. On 409 we offer the
+    // same overwrite / keep-both / cancel prompt that the legacy
+    // create-new flow used (via askConflict in dialogs.js).
     if (!relPath) {
       if (!editedFilename) return;
       const atFolder = ta.dataset.atFolder || "";
@@ -192,11 +195,35 @@
       if (r.ok) {
         if (typeof window.modals?.closeRouted === "function") window.modals.closeRouted();
         scheduleRefresh(parentOf(fullPath));
-      } else if (r.status === 409) {
-        alert(r.rawText || `A file at ${fullPath} already exists. Pick a different name.`);
-      } else {
-        alert((r.body && r.body.error) || r.rawText || `Create failed (HTTP ${r.status}).`);
+        return;
       }
+      if (r.status === 409 && typeof fo.askConflict === "function") {
+        const action = await fo.askConflict(fullPath);
+        if (action === "overwrite") {
+          // /save overwrites in place when the destination is a file —
+          // a plain re-POST does the right thing.
+          const r2 = await postJson(`${baseUrl}/files/save`, { path: fullPath, content });
+          if (r2.ok) {
+            if (typeof window.modals?.closeRouted === "function") window.modals.closeRouted();
+            scheduleRefresh(parentOf(fullPath));
+          } else {
+            alert((r2.body && r2.body.error) || `Save failed (HTTP ${r2.status}).`);
+          }
+        } else if (action === "keep-both" && typeof fo.withCollisionSuffix === "function") {
+          const altered = fo.withCollisionSuffix(fullPath);
+          const r2 = await postJson(`${baseUrl}/files/save`, { path: altered, content });
+          if (r2.ok) {
+            if (typeof window.modals?.closeRouted === "function") window.modals.closeRouted();
+            scheduleRefresh(parentOf(altered));
+          } else {
+            alert((r2.body && r2.body.error) || `Save failed (HTTP ${r2.status}).`);
+          }
+        }
+        // "cancel" → leave the modal open so the user can edit the
+        // filename and try again without losing typed content.
+        return;
+      }
+      alert((r.body && r.body.error) || r.rawText || `Create failed (HTTP ${r.status}).`);
       return;
     }