diff --git a/src/common.rs b/src/common.rs
index 69e3ec3..596a248 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -2101,6 +2101,17 @@ pub fn load_custom_client() {
         };
         read_custom_client(&data.trim());
     }
+
+    // Custom fork: hardcode enable-audio = N as the default. User can still flip it on in Settings.
+    // Reason: RustDesk's official custom.txt path requires ed25519-signed base64 (see
+    // read_custom_client at line 2191 — decode64 + sign::verify with key
+    // "5Qbwsde3unUcJBtrx9ZkvUmwFNoExHzpryHuPUdqlWM="), which we can't produce without the
+    // official signing key. So we bypass custom.txt and inject directly into DEFAULT_SETTINGS.
+    // entry().or_insert() preserves the priority chain: OVERWRITE_SETTINGS → CONFIG2 → DEFAULT_SETTINGS.
+    {
+        let mut defaults = config::DEFAULT_SETTINGS.write().unwrap();
+        defaults.entry("enable-audio".to_string()).or_insert("N".to_string());
+    }
 }
 
 fn read_custom_client_advanced_settings(