diff --git a/crates/lanspread-tauri-deno-ts/src-tauri/src/lib.rs b/crates/lanspread-tauri-deno-ts/src-tauri/src/lib.rs
index b7f08ae..6441f5d 100644
--- a/crates/lanspread-tauri-deno-ts/src-tauri/src/lib.rs
+++ b/crates/lanspread-tauri-deno-ts/src-tauri/src/lib.rs
@@ -1470,12 +1470,18 @@ fn sanitize_language(language: &str) -> String {
     }
 }
 
+/// Characters that `cmd.exe` interprets even when the argument was quoted,
+/// because batch scripts expand `%~4` textually into their own command lines.
+/// `"` would end the quoted argument and `%` starts variable expansion; the
+/// rest are command separators, redirection and the escape character.
+const CMD_UNSAFE_USERNAME_CHARS: [char; 7] = ['"', '%', '&', '|', '<', '>', '^'];
+
 #[cfg_attr(not(target_os = "windows"), allow(dead_code))]
 fn sanitize_username(username: &str) -> String {
     let cleaned = username
         .trim()
         .chars()
-        .filter(|c| !c.is_control() && *c != '"' && *c != '%')
+        .filter(|c| !c.is_control() && !CMD_UNSAFE_USERNAME_CHARS.contains(c))
         .take(MAX_USERNAME_CHARS)
         .collect::<String>();
 
@@ -6173,6 +6179,15 @@ mod tests {
                 username: DEFAULT_USERNAME.to_string(),
             }
         );
+        // cmd.exe metacharacters are stripped even inside a quoted argument;
+        // everything else, including spaces and non-ASCII letters, survives.
+        assert_eq!(
+            launch_settings("en", "Jörg & Co | x > y < z ^ !"),
+            LaunchSettings {
+                language: "en".to_string(),
+                username: "Jörg  Co  x  y  z  !".to_string(),
+            }
+        );
     }
 
     #[test]