diff --git a/openless-all/app/src-tauri/src/coordinator.rs b/openless-all/app/src-tauri/src/coordinator.rs
index a0a86d00..e137b2cb 100644
--- a/openless-all/app/src-tauri/src/coordinator.rs
+++ b/openless-all/app/src-tauri/src/coordinator.rs
@@ -2026,16 +2026,107 @@ fn should_try_non_tsf_insertion_fallback(
 fn insert_via_non_tsf_fallback(
     inner: &Arc<Inner>,
     polished: &str,
-    restore_clipboard: bool,
-    paste_shortcut: PasteShortcut,
+    _restore_clipboard: bool,
+    _paste_shortcut: PasteShortcut,
 ) -> InsertStatus {
-    if inner.inserter.insert_via_unicode_keystrokes(polished) == InsertStatus::Inserted {
-        log::info!("[windows-ime] TSF unavailable; inserted via Unicode SendInput");
-        InsertStatus::Inserted
-    } else {
-        inner
-            .inserter
-            .insert_via_clipboard_fallback(polished, restore_clipboard, paste_shortcut)
+    let status = finish_non_tsf_insertion_fallback(
+        || inner.inserter.insert_via_unicode_keystrokes(polished),
+        || inner.inserter.copy_fallback(polished),
+    );
+
+    match status {
+        InsertStatus::Inserted => {
+            log::warn!(
+                "[windows-ime] TSF unavailable; inserted via paced Unicode SendInput fallback"
+            );
+        }
+        InsertStatus::CopiedFallback => {
+            log::warn!(
+                "[windows-ime] TSF unavailable; Unicode SendInput failed, left text on clipboard"
+            );
+        }
+        InsertStatus::PasteSent | InsertStatus::Failed => {
+            log::warn!(
+                "[windows-ime] TSF unavailable; Unicode SendInput fallback failed and copy fallback failed"
+            );
+        }
+    }
+
+    status
+}
+
+#[cfg(any(target_os = "windows", test))]
+fn finish_non_tsf_insertion_fallback<U, C>(
+    mut unicode_fallback: U,
+    mut copy_only_fallback: C,
+) -> InsertStatus
+where
+    U: FnMut() -> InsertStatus,
+    C: FnMut() -> InsertStatus,
+{
+    match unicode_fallback() {
+        InsertStatus::Inserted => InsertStatus::Inserted,
+        InsertStatus::PasteSent | InsertStatus::CopiedFallback | InsertStatus::Failed => {
+            match copy_only_fallback() {
+                InsertStatus::CopiedFallback => InsertStatus::CopiedFallback,
+                // TextInserter::copy_fallback is copy-only: success is CopiedFallback.
+                // Treat any other status as failure so this helper never invents an insert.
+                InsertStatus::Inserted | InsertStatus::PasteSent | InsertStatus::Failed => {
+                    InsertStatus::Failed
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod non_tsf_fallback_tests {
+    use super::finish_non_tsf_insertion_fallback;
+    use crate::types::InsertStatus;
+
+    #[test]
+    fn unicode_fallback_runs_before_copy_fallback() {
+        let mut copy_called = false;
+        let status = finish_non_tsf_insertion_fallback(
+            || InsertStatus::Inserted,
+            || {
+                copy_called = true;
+                InsertStatus::CopiedFallback
+            },
+        );
+
+        assert_eq!(status, InsertStatus::Inserted);
+        assert!(!copy_called);
+    }
+
+    #[test]
+    fn copy_fallback_runs_after_unicode_failure() {
+        let mut copy_called = false;
+        let status = finish_non_tsf_insertion_fallback(
+            || InsertStatus::Failed,
+            || {
+                copy_called = true;
+                InsertStatus::CopiedFallback
+            },
+        );
+
+        assert_eq!(status, InsertStatus::CopiedFallback);
+        assert!(copy_called);
+    }
+
+    #[test]
+    fn double_failure_does_not_pretend_text_was_copied() {
+        let mut copy_called = false;
+        let status = finish_non_tsf_insertion_fallback(
+            || InsertStatus::Failed,
+            || {
+                copy_called = true;
+                InsertStatus::Failed
+            },
+        );
+
+        assert_eq!(status, InsertStatus::Failed);
+        assert!(copy_called);
     }
 }
 
diff --git a/openless-all/app/src-tauri/src/coordinator/dictation.rs b/openless-all/app/src-tauri/src/coordinator/dictation.rs
index 1f399825..2c138897 100644
--- a/openless-all/app/src-tauri/src/coordinator/dictation.rs
+++ b/openless-all/app/src-tauri/src/coordinator/dictation.rs
@@ -114,39 +114,7 @@ async fn run_streaming_polish(
     // from what the user actually sees\"。
     let (tx, rx) = std::sync::mpsc::channel::<String>();
     let typer_handle = tokio::task::spawn_blocking(move || {
-        let mut typed_text = String::new();
-        let mut first_failure: Option<String> = None;
-        let mut pending = String::new();
-        while let Ok(delta) = rx.recv() {
-            pending.push_str(&delta);
-            let flush_at = std::time::Instant::now() + STREAMING_INSERT_FLUSH_INTERVAL;
-            loop {
-                let now = std::time::Instant::now();
-                if now >= flush_at {
-                    break;
-                }
-                match rx.recv_timeout(flush_at.duration_since(now)) {
-                    Ok(delta) => pending.push_str(&delta),
-                    Err(std::sync::mpsc::RecvTimeoutError::Timeout) => break,
-                    Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => {
-                        first_failure =
-                            flush_streaming_insert_buffer(&mut pending, &mut typed_text);
-                        return (typed_text, first_failure);
-                    }
-                }
-            }
-            first_failure = flush_streaming_insert_buffer(&mut pending, &mut typed_text);
-            if first_failure.is_some() {
-                // 一旦类型链路出错（如 Secure Input 启用），后续 delta 全部丢弃，但仍
-                // 把 mpsc drain 完，避免发送端阻塞。
-                while rx.recv().is_ok() {}
-                break;
-            }
-        }
-        if first_failure.is_none() {
-            first_failure = flush_streaming_insert_buffer(&mut pending, &mut typed_text);
-        }
-        (typed_text, first_failure)
+        drain_streaming_insert_deltas(rx, STREAMING_INSERT_FLUSH_INTERVAL)
     });
 
     // 3. 调流式润色，on_delta 塞 mpsc；should_cancel 检查 dictation 取消旗。
@@ -283,13 +251,77 @@ async fn run_streaming_polish(
     }
 }
 
+fn drain_streaming_insert_deltas(
+    rx: std::sync::mpsc::Receiver<String>,
+    flush_interval: std::time::Duration,
+) -> (String, Option<String>) {
+    drain_streaming_insert_deltas_with(rx, flush_interval, flush_streaming_insert_buffer)
+}
+
+fn drain_streaming_insert_deltas_with<F>(
+    rx: std::sync::mpsc::Receiver<String>,
+    flush_interval: std::time::Duration,
+    mut flush_pending: F,
+) -> (String, Option<String>)
+where
+    F: FnMut(&mut String, &mut String) -> Option<String>,
+{
+    let mut typed_text = String::new();
+    let mut first_failure: Option<String> = None;
+    let mut pending = String::new();
+    while let Ok(delta) = rx.recv() {
+        pending.push_str(&delta);
+        let flush_at = std::time::Instant::now() + flush_interval;
+        loop {
+            let now = std::time::Instant::now();
+            if now >= flush_at {
+                break;
+            }
+            match rx.recv_timeout(flush_at.duration_since(now)) {
+                Ok(delta) => pending.push_str(&delta),
+                Err(std::sync::mpsc::RecvTimeoutError::Timeout) => break,
+                Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => {
+                    first_failure = flush_pending(&mut pending, &mut typed_text);
+                    return (typed_text, first_failure);
+                }
+            }
+        }
+        first_failure = flush_pending(&mut pending, &mut typed_text);
+        if first_failure.is_some() {
+            // 一旦类型链路出错（如 Secure Input 启用），后续 delta 全部丢弃，但仍
+            // 把 mpsc drain 完，避免发送端阻塞。
+            while rx.recv().is_ok() {}
+            break;
+        }
+    }
+    if first_failure.is_none() {
+        first_failure = flush_pending(&mut pending, &mut typed_text);
+    }
+    (typed_text, first_failure)
+}
+
 fn flush_streaming_insert_buffer(pending: &mut String, typed_text: &mut String) -> Option<String> {
+    flush_streaming_insert_buffer_with(
+        pending,
+        typed_text,
+        crate::unicode_keystroke::type_unicode_chunk,
+    )
+}
+
+fn flush_streaming_insert_buffer_with<F>(
+    pending: &mut String,
+    typed_text: &mut String,
+    mut type_chunk: F,
+) -> Option<String>
+where
+    F: FnMut(&str) -> Result<usize, crate::unicode_keystroke::TypeError>,
+{
     if pending.is_empty() {
         return None;
     }
     let delta = std::mem::take(pending);
     let delta_chars = delta.chars().count();
-    match crate::unicode_keystroke::type_unicode_chunk(&delta) {
+    match type_chunk(&delta) {
         Ok(typed_chars) => {
             let appended = append_typed_prefix(typed_text, &delta, typed_chars);
             if appended < delta_chars {
@@ -362,9 +394,7 @@ fn streaming_insert_eligible(
     mode: PolishMode,
     raw_uses_llm: bool,
 ) -> bool {
-    streaming_insert_enabled
-        && !translation_active
-        && (mode != PolishMode::Raw || raw_uses_llm)
+    streaming_insert_enabled && !translation_active && (mode != PolishMode::Raw || raw_uses_llm)
 }
 
 fn default_done_message(status: InsertStatus, polish_failed: bool) -> Option<String> {
@@ -1728,8 +1758,8 @@ fn append_typed_prefix(target: &mut String, delta: &str, typed_chars: usize) ->
 #[cfg(test)]
 mod tests {
     use super::{
-        append_typed_prefix, default_done_message, dictation_error_code,
-        finalize_polished_text, streaming_insert_eligible,
+        append_typed_prefix, default_done_message, drain_streaming_insert_deltas_with,
+        finalize_polished_text, flush_streaming_insert_buffer_with, streaming_insert_eligible,
     };
     use crate::types::{ChineseScriptPreference, CorrectionRule, InsertStatus, PolishMode};
 
@@ -1836,4 +1866,61 @@ mod tests {
             Some("润色失败，已插入原文".to_string())
         );
     }
+
+    #[test]
+    fn streaming_insert_batches_queued_deltas_before_flush() {
+        let (tx, rx) = std::sync::mpsc::channel();
+        tx.send("你".to_string()).unwrap();
+        tx.send("好".to_string()).unwrap();
+        tx.send("🙂".to_string()).unwrap();
+        drop(tx);
+
+        let mut flushed = Vec::new();
+        let (typed, failure) = drain_streaming_insert_deltas_with(
+            rx,
+            std::time::Duration::from_millis(50),
+            |pending, typed_text| {
+                flushed.push(pending.clone());
+                typed_text.push_str(pending);
+                pending.clear();
+                None
+            },
+        );
+
+        assert_eq!(flushed, vec!["你好🙂".to_string()]);
+        assert_eq!(typed, "你好🙂");
+        assert_eq!(failure, None);
+    }
+
+    #[test]
+    fn flush_streaming_insert_buffer_keeps_partial_unicode_prefix() {
+        let mut pending = "a你🙂b".to_string();
+        let mut typed = String::new();
+
+        let failure = flush_streaming_insert_buffer_with(&mut pending, &mut typed, |_| {
+            Err(crate::unicode_keystroke::TypeError::Partial {
+                typed_chars: 3,
+                source: Box::new(platform_type_error()),
+            })
+        });
+
+        assert_eq!(typed, "a你🙂");
+        assert!(pending.is_empty());
+        assert!(failure.is_some());
+    }
+
+    #[cfg(target_os = "macos")]
+    fn platform_type_error() -> crate::unicode_keystroke::TypeError {
+        crate::unicode_keystroke::TypeError::EventAllocFailed
+    }
+
+    #[cfg(target_os = "windows")]
+    fn platform_type_error() -> crate::unicode_keystroke::TypeError {
+        crate::unicode_keystroke::TypeError::SendInputFailed("fail".into())
+    }
+
+    #[cfg(target_os = "linux")]
+    fn platform_type_error() -> crate::unicode_keystroke::TypeError {
+        crate::unicode_keystroke::TypeError::EnigoText("fail".into())
+    }
 }
diff --git a/openless-all/app/src-tauri/src/insertion.rs b/openless-all/app/src-tauri/src/insertion.rs
index 9b1d6567..b5ca39b4 100644
--- a/openless-all/app/src-tauri/src/insertion.rs
+++ b/openless-all/app/src-tauri/src/insertion.rs
@@ -386,15 +386,30 @@ fn insertion_success_status() -> InsertStatus {
 
 #[cfg(target_os = "windows")]
 mod windows_unicode {
+    use std::time::Duration;
+
     use windows::Win32::UI::Input::KeyboardAndMouse::{
         SendInput, INPUT, INPUT_0, INPUT_KEYBOARD, KEYBDINPUT, KEYBD_EVENT_FLAGS, KEYEVENTF_KEYUP,
         KEYEVENTF_UNICODE, VIRTUAL_KEY,
     };
 
+    const SENDINPUT_CHUNK_CHARS: usize = 16;
+    const SENDINPUT_CHUNK_DELAY: Duration = Duration::from_millis(12);
+
     pub fn send_text(text: &str) -> Result<(), String> {
-        for unit in text.encode_utf16() {
-            send_utf16_unit(unit, false)?;
-            send_utf16_unit(unit, true)?;
+        let mut sent_in_chunk = 0usize;
+        let mut chars = text.chars().peekable();
+        while let Some(ch) = chars.next() {
+            let mut buf = [0u16; 2];
+            for unit in ch.encode_utf16(&mut buf) {
+                send_utf16_unit(*unit, false)?;
+                send_utf16_unit(*unit, true)?;
+            }
+            sent_in_chunk += 1;
+            if sent_in_chunk >= SENDINPUT_CHUNK_CHARS && chars.peek().is_some() {
+                std::thread::sleep(SENDINPUT_CHUNK_DELAY);
+                sent_in_chunk = 0;
+            }
         }
         Ok(())
     }
diff --git a/openless-all/app/src-tauri/src/types.rs b/openless-all/app/src-tauri/src/types.rs
index 0b8b3752..0feb78de 100644
--- a/openless-all/app/src-tauri/src/types.rs
+++ b/openless-all/app/src-tauri/src/types.rs
@@ -544,7 +544,8 @@ pub struct UserPreferences {
     /// 行为一致，不破坏既有用户。
     #[serde(default)]
     pub paste_shortcut: PasteShortcut,
-    /// Windows: 是否允许 TSF 失败后继续使用 SendInput / 粘贴类非 TSF 兜底。
+    /// Windows: 是否允许 TSF 失败后继续使用分批 Unicode SendInput / 剪贴板兜底。
+    /// Unicode SendInput 失败时才复制到剪贴板，避免文本丢失。
     /// 默认开启以保持可用性；关闭后可验证文本是否真正由 TSF 上屏。
     #[serde(default = "default_true")]
     pub allow_non_tsf_insertion_fallback: bool,
diff --git a/openless-all/app/src/i18n/en.ts b/openless-all/app/src/i18n/en.ts
index 3b177f83..225a4537 100644
--- a/openless-all/app/src/i18n/en.ts
+++ b/openless-all/app/src/i18n/en.ts
@@ -546,7 +546,7 @@ export const en: typeof zhCN = {
       comboClear: 'Clear',
       comboConflict: 'This shortcut combination is not available',
       allowNonTsfFallbackLabel: 'Allow non-TSF fallback',
-      allowNonTsfFallbackDesc: 'Windows: when TSF insertion fails, allow Unicode SendInput / shortcut paste.',
+      allowNonTsfFallbackDesc: 'Windows: when TSF insertion fails, use paced Unicode SendInput; if that still fails, copy the text to the clipboard.',
       historyGroupTitle: 'History & context',
       historyRetentionLabel: 'History retention (days)',
       historyRetentionDesc: 'Entries older than this are pruned on new writes; 0 = no time-based pruning.',
diff --git a/openless-all/app/src/i18n/ja.ts b/openless-all/app/src/i18n/ja.ts
index d7479197..760baa83 100644
--- a/openless-all/app/src/i18n/ja.ts
+++ b/openless-all/app/src/i18n/ja.ts
@@ -548,7 +548,7 @@ export const ja: typeof zhCN = {
       comboClear: 'クリア',
       comboConflict: 'このショートカットの組み合わせは使用できません',
       allowNonTsfFallbackLabel: '非 TSF フォールバックを許可',
-      allowNonTsfFallbackDesc: 'Windows：TSF 入力が失敗した時に Unicode SendInput / ショートカットペーストへの切替を許可。',
+      allowNonTsfFallbackDesc: 'Windows：TSF 入力が失敗した時は分割した Unicode SendInput を使い、それも失敗した場合はクリップボードへコピーします。',
       historyGroupTitle: '履歴とコンテキスト',
       historyRetentionLabel: '履歴保持期間（日）',
       historyRetentionDesc: '保持日数を超えた履歴は新規書き込み時に削除されます。0 = 時間で削除しない。',
diff --git a/openless-all/app/src/i18n/ko.ts b/openless-all/app/src/i18n/ko.ts
index dbd068b1..c6d4de87 100644
--- a/openless-all/app/src/i18n/ko.ts
+++ b/openless-all/app/src/i18n/ko.ts
@@ -548,7 +548,7 @@ export const ko: typeof zhCN = {
       comboClear: '지우기',
       comboConflict: '이 단축키 조합은 사용할 수 없습니다',
       allowNonTsfFallbackLabel: '비 TSF 폴백 허용',
-      allowNonTsfFallbackDesc: 'Windows: TSF 입력 실패 시 Unicode SendInput / 단축키 붙여넣기로 전환 허용.',
+      allowNonTsfFallbackDesc: 'Windows: TSF 입력이 실패하면 분할된 Unicode SendInput을 사용하고, 그래도 실패하면 텍스트를 클립보드에 복사합니다.',
       historyGroupTitle: '기록 및 컨텍스트',
       historyRetentionLabel: '기록 보관 기간(일)',
       historyRetentionDesc: '보관 기간을 초과한 기록은 새 항목 작성 시 정리됩니다. 0 = 시간 기반 정리 비활성화.',
diff --git a/openless-all/app/src/i18n/zh-CN.ts b/openless-all/app/src/i18n/zh-CN.ts
index 089cbbbe..b32d04b2 100644
--- a/openless-all/app/src/i18n/zh-CN.ts
+++ b/openless-all/app/src/i18n/zh-CN.ts
@@ -544,7 +544,7 @@ export const zhCN = {
       comboClear: '清除',
       comboConflict: '该快捷键组合不可用',
       allowNonTsfFallbackLabel: '允许非 TSF 兜底',
-      allowNonTsfFallbackDesc: 'Windows：TSF 失败时改用 Unicode SendInput / 快捷键粘贴。',
+      allowNonTsfFallbackDesc: 'Windows：TSF 失败时使用分批 Unicode SendInput；如果仍失败，再复制到剪贴板。',
       historyGroupTitle: '历史与上下文',
       historyRetentionLabel: '历史保留天数',
       historyRetentionDesc: '超过保留天数的历史在写入新条目时被清理；0 = 不按时间清理。',
diff --git a/openless-all/app/src/i18n/zh-TW.ts b/openless-all/app/src/i18n/zh-TW.ts
index 34a11160..8f31b52e 100644
--- a/openless-all/app/src/i18n/zh-TW.ts
+++ b/openless-all/app/src/i18n/zh-TW.ts
@@ -546,7 +546,7 @@ export const zhTW: typeof zhCN = {
       pasteShortcutCtrlShiftV: 'Ctrl+Shift+V（kitty / alacritty / wezterm / 多數終端）',
       pasteShortcutShiftInsert: 'Shift+Insert（xterm / urxvt）',
       allowNonTsfFallbackLabel: '允許非 TSF 兜底',
-      allowNonTsfFallbackDesc: 'Windows：TSF 失敗時改用 Unicode SendInput / 快捷鍵粘貼。',
+      allowNonTsfFallbackDesc: 'Windows：TSF 失敗時使用分批 Unicode SendInput；如果仍失敗，再複製到剪貼簿。',
       historyGroupTitle: '歷史與上下文',
       historyRetentionLabel: '歷史保留天數',
       historyRetentionDesc: '超過保留天數的歷史在寫入新條目時被清理；0 = 不按時間清理。',
diff --git a/openless-all/app/src/lib/types.ts b/openless-all/app/src/lib/types.ts
index 67ff09e5..21a6a722 100644
--- a/openless-all/app/src/lib/types.ts
+++ b/openless-all/app/src/lib/types.ts
@@ -230,7 +230,7 @@ export interface UserPreferences {
    *  等终端只接受 Ctrl+Shift+V，硬编码 Ctrl+V 会被吞掉，听写文本只剩在剪贴板里。
    *  macOS 走 AX 直写不受影响。默认 'ctrlV' 与历史行为一致。 */
   pasteShortcut: PasteShortcut;
-  /** Windows：TSF 失败后是否允许 SendInput / 粘贴类非 TSF 兜底。关闭后可验证是否真实 TSF 上屏。 */
+  /** Windows：TSF 失败后是否允许快捷键粘贴 / 剪贴板兜底。仅在剪贴板写失败时才再试 SendInput。关闭后可验证是否真实 TSF 上屏。 */
   allowNonTsfInsertionFallback: boolean;
   /** 用户的工作语言（多选，原生名）；作为前提注入 LLM polish/translate prompt 头部。 */
   workingLanguages: string[];