diff --git a/package.json b/package.json
index ad2927c..975b520 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "iccery",
   "private": true,
-  "version": "0.5.0",
+  "version": "0.5.1",
   "type": "module",
   "scripts": {
     "fetch-argyll": "node scripts/fetch-argyll.mjs",
diff --git a/src-tauri/Cargo.toml b/src-tauri/Cargo.toml
index f602906..969817f 100644
--- a/src-tauri/Cargo.toml
+++ b/src-tauri/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "iccery"
-version = "0.5.0"
+version = "0.5.1"
 description = "Modern Printer Profiling UI frontend for ArgyllCMS"
 authors = ["Gordon"]
 edition = "2021"
diff --git a/src-tauri/src/commands.rs b/src-tauri/src/commands.rs
index d171a83..3e74972 100644
--- a/src-tauri/src/commands.rs
+++ b/src-tauri/src/commands.rs
@@ -30,6 +30,13 @@ pub async fn kill_process(
     state.kill(&id).await
 }
 
+#[tauri::command]
+pub async fn kill_all_processes(
+    state: State<'_, ProcessManager>,
+) -> Result<usize, String> {
+    Ok(state.kill_all().await)
+}
+
 pub fn get_binary_candidates(binary_name: &str) -> Vec<String> {
     if cfg!(windows) && !binary_name.to_lowercase().ends_with(".exe") {
         vec![format!("{}.exe", binary_name), binary_name.to_string()]
diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
index b3d248c..837ea38 100644
--- a/src-tauri/src/lib.rs
+++ b/src-tauri/src/lib.rs
@@ -1,3 +1,5 @@
+use tauri::Manager;
+
 mod commands;
 mod events;
 mod print;
@@ -39,6 +41,7 @@ pub fn run() {
             commands::select_directory,
             commands::send_stdin,
             commands::kill_process,
+            commands::kill_all_processes,
             commands::resolve_binary,
             commands::detect_instruments,
             commands::get_profile_path,
@@ -66,6 +69,26 @@ pub fn run() {
             settings::export_preset_json,
             settings::import_preset_json,
         ])
-        .run(tauri::generate_context!())
-        .expect("error while running tauri application");
+        .build(tauri::generate_context!())
+        .expect("error while building tauri application")
+        .run(|app_handle, event| {
+            match event {
+                tauri::RunEvent::Exit | tauri::RunEvent::ExitRequested { .. } => {
+                    let pm = app_handle.state::<process_manager::ProcessManager>();
+                    tauri::async_runtime::block_on(async {
+                        pm.kill_all().await;
+                    });
+                }
+                tauri::RunEvent::WindowEvent {
+                    event: tauri::WindowEvent::CloseRequested { .. },
+                    ..
+                } => {
+                    let pm = app_handle.state::<process_manager::ProcessManager>();
+                    tauri::async_runtime::block_on(async {
+                        pm.kill_all().await;
+                    });
+                }
+                _ => {}
+            }
+        });
 }
diff --git a/src-tauri/src/process_manager.rs b/src-tauri/src/process_manager.rs
index 594bd48..904925f 100644
--- a/src-tauri/src/process_manager.rs
+++ b/src-tauri/src/process_manager.rs
@@ -168,6 +168,38 @@ impl ProcessManager {
         }
         Err("Process not found".to_string())
     }
+
+    /// Kills all currently managed subprocesses, closes their stdins, and signals termination.
+    /// Returns the number of processes signaled.
+    pub async fn kill_all(&self) -> usize {
+        // 1. Close and drop all stdin streams
+        {
+            let mut stdins = self.stdins.lock().await;
+            stdins.clear();
+        }
+
+        // 2. Extract and send kill signal to all active killer channels
+        let killers_to_signal = {
+            let mut killers = self.killers.lock().await;
+            let list: Vec<(String, tokio::sync::oneshot::Sender<()>)> = killers.drain().collect();
+            list
+        };
+
+        let count = killers_to_signal.len();
+        if count > 0 {
+            log::info!(target: "subprocess", "Terminating all managed subprocesses ({count} active)");
+        }
+
+        for (id, killer) in killers_to_signal {
+            log::info!(target: "subprocess", "Sending kill signal to subprocess '{id}'");
+            let _ = killer.send(());
+        }
+
+        // Give background tasks a brief moment to initiate child.start_kill()
+        tokio::time::sleep(tokio::time::Duration::from_millis(50)).await;
+
+        count
+    }
 }
 
 #[cfg(test)]
@@ -183,4 +215,33 @@ mod tests {
             assert!(!stdins.contains_key("test_proc"));
         }
     }
+
+    #[tokio::test]
+    async fn test_kill_all_cleans_maps() {
+        let pm = ProcessManager::new();
+
+        let (tx1, mut rx1) = tokio::sync::oneshot::channel::<()>();
+        let (tx2, mut rx2) = tokio::sync::oneshot::channel::<()>();
+
+        {
+            let mut killers = pm.killers.lock().await;
+            killers.insert("proc_1".to_string(), tx1);
+            killers.insert("proc_2".to_string(), tx2);
+        }
+
+        let killed_count = pm.kill_all().await;
+        assert_eq!(killed_count, 2);
+
+        // Verify channels received signal
+        assert!(rx1.try_recv().is_ok());
+        assert!(rx2.try_recv().is_ok());
+
+        // Verify maps are empty
+        {
+            let stdins = pm.stdins.lock().await;
+            let killers = pm.killers.lock().await;
+            assert!(stdins.is_empty());
+            assert!(killers.is_empty());
+        }
+    }
 }
diff --git a/src-tauri/tauri.conf.json b/src-tauri/tauri.conf.json
index 0e5c631..ffdc4f1 100644
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ICCery",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "identifier": "com.gronod.iccery",
   "build": {
     "frontendDist": "../src"