diff --git a/CHANGELOG.md b/CHANGELOG.md
index 234a762..1ab7c19 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- **Save ink into file says so when a file can't take ink** (v37, HTML overlay). Picking a file without OverBoard in it now shows **Not saved!** on the button and explains in plain words (drop it on the app first to make a board copy), and the browser no longer asks to edit a file that won't be written to.
 - **Save ink into file works into a different board copy in Chrome** (v36, HTML overlay). Saving from `pet_board_inked.html` into `pet_board_clean.html` now asks Chrome's "allow editing?" question straight after you pick the file, before OverBoard's own "different file name" question (which used up the tap Chrome needs). If the browser still won't ask, the button stays in view and says **Tap again to allow**.
 - **Ink saved into a file always shows when that file opens** (v36). The file now notes when the ink was written into it, so a browser that had used that copy before (even just to try it and clear it) no longer shows its own older, empty copy instead.
 - **Tested: old board copies upgrade cleanly** (v35). Dropping an older `_board.html` on the PDF app keeps its name (no `_board_board`), puts in the newest toolbar, and the ink saved inside it still opens. A test now checks this end to end, starting from a v13 board copy.
diff --git a/app/index.html b/app/index.html
index 57ac23b..29bc1fb 100644
--- a/app/index.html
+++ b/app/index.html
@@ -5,7 +5,7 @@
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <title>OverBoard PDF</title>
 <meta name="description" content="OverBoard: write on any PDF on your smartboard. Runs in the browser; nothing is uploaded.">
-<meta name="ob-version" content="38fc581fca25">
+<meta name="ob-version" content="7bce951ceba7">
 <meta name="theme-color" content="#1f1f1f">
 <link rel="manifest" href="manifest.json">
 <link rel="icon" href="icons/icon-192.png">
@@ -45,7 +45,7 @@ <h2 data-t="open_again">Open again</h2>
     <p class="note"><span data-th="start_note">Your PDF and your ink stay in this browser on this computer. Nothing is uploaded.
       Have a Word file? In Word, choose File → Save as PDF, then drop the PDF here.
       Have an HTML worksheet? Drop it here to get a <i>_board.html</i> copy you can write on.</span>
-      <br><a href="../" data-t="back_demo">Back to the HTML worksheet demo</a> · <a href="https://github.com/BPMData/OverBoard" data-t="about">About OverBoard</a> · <a href="report/?from=start" target="_blank" data-t="board_help">Board not working?</a> · <span id="ob-release" title="OverBoard version">v36</span></p>
+      <br><a href="../" data-t="back_demo">Back to the HTML worksheet demo</a> · <a href="https://github.com/BPMData/OverBoard" data-t="about">About OverBoard</a> · <a href="report/?from=start" target="_blank" data-t="board_help">Board not working?</a> · <span id="ob-release" title="OverBoard version">v37</span></p>
     <p class="note ob-langpick"><label><span aria-hidden="true">🌐</span> <select id="ob-lang" aria-label="Language" data-ta="language" data-tt="language" title="Language"></select></label></p>
   </div>
 </main>
diff --git a/app/report/index.html b/app/report/index.html
index 2d9588e..dcdaaeb 100644
--- a/app/report/index.html
+++ b/app/report/index.html
@@ -97,7 +97,7 @@ <h1 data-t="r_h1">Is OverBoard not working on your board?</h1>
     <p data-th="r_intro2">If something doesn't work the way the page asks, that's fine. <b>That's exactly what I need to know.</b> Just keep going.</p>
     <p class="mute small" data-th="r_privacy">Nothing is sent until you press <b>Send</b> at the very end, and you'll see everything first. No worksheets, PDFs or ink are ever included.</p>
     <div class="row"><button class="go big" data-go="start" data-t="r_start">Start</button></div>
-    <p class="mute small" style="margin-top:28px">OverBoard <span id="ob-release" title="OverBoard version">v36</span></p>
+    <p class="mute small" style="margin-top:28px">OverBoard <span id="ob-release" title="OverBoard version">v37</span></p>
   </div></div>
 </section>
 
diff --git a/app/sw.js b/app/sw.js
index b49c960..c59902d 100644
--- a/app/sw.js
+++ b/app/sw.js
@@ -1,9 +1,9 @@
 // ===== GENERATED by tools/build.py: every file the app needs, with the start of its SHA-256. Do not edit by hand. =====
-const VERSION = '471e7c21ebea';
+const VERSION = '132eb34e5d4f';
 const FILES = {
-  "../overlay/ink_overlay.html": "42bade453c738a0a",
+  "../overlay/ink_overlay.html": "b6c60b7242623972",
   "../shared/ink-core.js": "84be8f49eeb4d2d3",
-  "../shared/strings.js": "d85fbc3cf3f1c436",
+  "../shared/strings.js": "60ed5521f07e5d9f",
   "../shared/toolbar.css": "55e88770a7c0f1c2",
   "app.css": "eb0f282d02685caf",
   "embed.js": "ea50a9ff4e960dd4",
@@ -14,14 +14,14 @@ const FILES = {
   "icons/icon-192.png": "d245e15b36475003",
   "icons/icon-512.png": "17c1021fe2a0ade1",
   "icons/maskable-512.png": "0c58f1bdccc9eda9",
-  "index.html": "c03b8fc0802c288d",
+  "index.html": "79fae83f812a179f",
   "ink.js": "253f8d907ccfbc1b",
   "libs.js": "c09f60186ab9029a",
   "main.js": "48ecaa409acb49b9",
   "manifest.json": "f7ee4a6c6f83cd40",
   "notebook.js": "47bcfd4f80712344",
   "offline.js": "6504935b2738711a",
-  "report/index.html": "9c8cd50b68eafb8c",
+  "report/index.html": "5be61cdfda281b62",
   "store.js": "66af54cd32e6cbd2",
   "textlayer.js": "1911308ed3e2a8b5",
   "vendor/pdf-lib@1.17.1/LICENSE.md": "f2c9fc00fdb66eb9",
@@ -214,7 +214,7 @@ const FILES = {
   "vendor/pdfjs-dist@4.10.38/standard_fonts/LiberationSans-BoldItalic.ttf": "a224075ac17495ad",
   "vendor/pdfjs-dist@4.10.38/standard_fonts/LiberationSans-Italic.ttf": "832b4406dbef2362",
   "vendor/pdfjs-dist@4.10.38/standard_fonts/LiberationSans-Regular.ttf": "f8ace1f892b2bd9d",
-  "version.json": "0c4d0798795a815b",
+  "version.json": "8579eaae05ca65ca",
   "viewer.js": "648b4479c5b68b93"
 };
 // ===== END GENERATED =====
diff --git a/app/version.json b/app/version.json
index 19641e2..7c07d85 100644
--- a/app/version.json
+++ b/app/version.json
@@ -1,5 +1,5 @@
 {
-  "v": "38fc581fca25",
+  "v": "7bce951ceba7",
   "js": [
     "embed.js",
     "export.js",
diff --git a/index.html b/index.html
index 0e1897d..17fd268 100644
--- a/index.html
+++ b/index.html
@@ -54,7 +54,7 @@ <h2>Exit ticket</h2>
   <div class="lines"><div></div><div></div><div></div><div></div></div>
   <div class="foot">OverBoard · page 2 / 2 · Your ink saves in this browser only. Nothing is uploaded.</div>
 </div>
-<!-- ===== INK OVERLAY START (v36) =====
+<!-- ===== INK OVERLAY START (v37) =====
   Smartboard writing layer. Paste this whole block just before </body> in any .html file.
   SMART BOARD: pen tip writes. Palm, fist or side of hand erases (the board reports it as an eraser).
   Finger (and the round end of the SMART pen) scrolls the page; the "Finger" button switches it to drawing if you lose the pen.
@@ -1622,7 +1622,7 @@ <h2>Exit ticket</h2>
       "saved_flash": ["Saved!", "¡Guardado!", "已保存！", "Na-save!", "Đã lưu!", "Enregistré !", "Salvo!", "تم الحفظ!"],
       "not_saved": ["Not saved!", "¡No se guardó!", "未保存！", "Hindi na-save!", "Chưa lưu!", "Non enregistré !", "Não salvo!", "لم يُحفظ!"],
       "confirm_other_file": ["This page is \"{a}\" but you picked \"{b}\". Save ink into the picked file?", "Esta página es \"{a}\" pero elegiste \"{b}\". ¿Guardar la tinta en el archivo elegido?", "此页面是“{a}”，但你选择了“{b}”。要把笔迹保存到所选文件吗？", "Ang pahinang ito ay \"{a}\" pero \"{b}\" ang pinili mo. I-save ang tinta sa napiling file?", "Trang này là \"{a}\" nhưng bạn đã chọn \"{b}\". Lưu nét mực vào tệp đã chọn?", "Cette page est « {a} » mais vous avez choisi « {b} ». Enregistrer l'encre dans le fichier choisi ?", "Esta página é \"{a}\", mas você escolheu \"{b}\". Salvar a tinta no arquivo escolhido?", "هذه الصفحة هي \"{a}\" لكنك اخترت \"{b}\". هل تحفظ الحبر في الملف المختار؟"],
-      "st_no_ink_block": ["That file has no ink block. Paste the overlay snippet into it first.", "Ese archivo no tiene bloque de tinta. Primero pega en él el código de OverBoard.", "该文件没有笔迹区块。请先把 OverBoard 代码粘贴进去。", "Walang ink block ang file na iyan. I-paste muna roon ang OverBoard snippet.", "Tệp đó không có khối nét mực. Hãy dán đoạn mã OverBoard vào trước.", "Ce fichier n'a pas de bloc d'encre. Collez-y d'abord le code d'OverBoard.", "Esse arquivo não tem bloco de tinta. Cole o código do OverBoard nele primeiro.", "هذا الملف لا يحتوي على كتلة الحبر. الصق شيفرة OverBoard فيه أولًا."],
+      "st_no_ink_block": ["That file doesn't have OverBoard in it, so it can't keep ink. Drop it on the OverBoard app first to make a board copy.", "Ese archivo no tiene OverBoard, así que no puede guardar tinta. Primero suéltalo en la app de OverBoard para hacer una copia para la pizarra.", "该文件里没有 OverBoard，无法保存笔迹。请先把它拖到 OverBoard 应用里，生成一份白板副本。", "Walang OverBoard ang file na iyan, kaya hindi ito makakapag-save ng tinta. I-drop muna ito sa OverBoard app para gumawa ng kopya para sa board.", "Tệp đó không có OverBoard nên không lưu được nét mực. Hãy thả nó vào ứng dụng OverBoard trước để tạo bản dùng trên bảng.", "Ce fichier ne contient pas OverBoard, il ne peut donc pas garder l'encre. Déposez-le d'abord sur l'app OverBoard pour en faire une copie pour le tableau.", "Esse arquivo não tem o OverBoard, então não guarda tinta. Primeiro solte-o no app OverBoard para fazer uma cópia para a lousa.", "هذا الملف لا يحتوي على OverBoard، لذا لا يمكنه حفظ الحبر. اسحبه أولًا إلى تطبيق OverBoard لإنشاء نسخة للسبورة."],
       "st_tap_allow": ["{p} · tap Save ink into file to allow writing", "{p} · toca Guardar tinta en el archivo para permitir escribir", "{p} · 点按“把笔迹保存到文件”以允许写入", "{p} · i-tap ang I-save ang tinta sa file para payagang magsulat", "{p} · chạm Lưu nét mực vào tệp để cho phép ghi", "{p} · touchez Enregistrer l'encre dans le fichier pour autoriser l'écriture", "{p} · toque em Salvar tinta no arquivo para permitir gravar", "{p} · اضغط «حفظ الحبر في الملف» للسماح بالكتابة"],
       "st_linked_no_block": ["Linked file has no ink block", "El archivo vinculado no tiene bloque de tinta", "关联文件没有笔迹区块", "Walang ink block ang naka-link na file", "Tệp liên kết không có khối nét mực", "Le fichier lié n'a pas de bloc d'encre", "O arquivo vinculado não tem bloco de tinta", "الملف المرتبط لا يحتوي على كتلة الحبر"],
       "st_saved_to": ["{p} · saved to {f} {t}", "{p} · guardado en {f} {t}", "{p} · 已保存到 {f} {t}", "{p} · na-save sa {f} {t}", "{p} · đã lưu vào {f} {t}", "{p} · enregistré dans {f} {t}", "{p} · salvo em {f} {t}", "{p} · حُفظ في {f} {t}"],
@@ -2282,12 +2282,13 @@ <h2>Exit ticket</h2>
   async function linkFile(){
     var hs = await window.showOpenFilePicker({ types: [{ description: 'This worksheet (.html)', accept: { 'text/html': ['.html', '.htm'] } }] });
     var h = hs[0], base = decodeURIComponent(location.pathname.split('/').pop());
+    // a file without OverBoard in it has nowhere to keep ink: say so before the browser asks to edit it
+    var txt = await (await h.getFile()).text();
+    if (injectInk(txt, '{}') === null) { setStatus(tr('st_no_ink_block')); return 'none'; }
     // ask to write right away, while the tap that opened the file window still counts: in Chrome, our question
     // below uses it up, and then the browser refuses without asking
     try { if ((await h.queryPermission({ mode: 'readwrite' })) !== 'granted') await h.requestPermission({ mode: 'readwrite' }); } catch(e){}
     if (base && h.name !== base && !confirm(tr('confirm_other_file', { a: base, b: h.name }))) return false;
-    var txt = await (await h.getFile()).text();
-    if (injectInk(txt, '{}') === null) { setStatus(tr('st_no_ink_block')); return false; }
     fileHandle = h; idb('readwrite', function(st){ return st.put(h, KEY); });
     return true;
   }
@@ -2312,7 +2313,7 @@ <h2>Exit ticket</h2>
   async function saveFile(forcePick){   // true = ink written into the file, false = not (status line says why), null = picker cancelled
     if (!FSA) { setStatus(tr('st_needs_chrome')); return false; }
     try {
-      if (forcePick || !fileHandle) { if (!(await linkFile())) return null; }
+      if (forcePick || !fileHandle) { var linked = await linkFile(); if (linked === 'none') return false; if (!linked) return null; }   // false: Not saved! on the button
       writeLocal(true);
       for (var i = 0; fileBusy && i < 30; i++) await new Promise(function(r){ setTimeout(r, 100); });   // let an autosave finish first
       return await writeFile(true);
diff --git a/overlay/ink_overlay.html b/overlay/ink_overlay.html
index 4fd01e8..f9c27c2 100644
--- a/overlay/ink_overlay.html
+++ b/overlay/ink_overlay.html
@@ -1,4 +1,4 @@
-<!-- ===== INK OVERLAY START (v36) =====
+<!-- ===== INK OVERLAY START (v37) =====
   Smartboard writing layer. Paste this whole block just before </body> in any .html file.
   SMART BOARD: pen tip writes. Palm, fist or side of hand erases (the board reports it as an eraser).
   Finger (and the round end of the SMART pen) scrolls the page; the "Finger" button switches it to drawing if you lose the pen.
@@ -1566,7 +1566,7 @@
       "saved_flash": ["Saved!", "¡Guardado!", "已保存！", "Na-save!", "Đã lưu!", "Enregistré !", "Salvo!", "تم الحفظ!"],
       "not_saved": ["Not saved!", "¡No se guardó!", "未保存！", "Hindi na-save!", "Chưa lưu!", "Non enregistré !", "Não salvo!", "لم يُحفظ!"],
       "confirm_other_file": ["This page is \"{a}\" but you picked \"{b}\". Save ink into the picked file?", "Esta página es \"{a}\" pero elegiste \"{b}\". ¿Guardar la tinta en el archivo elegido?", "此页面是“{a}”，但你选择了“{b}”。要把笔迹保存到所选文件吗？", "Ang pahinang ito ay \"{a}\" pero \"{b}\" ang pinili mo. I-save ang tinta sa napiling file?", "Trang này là \"{a}\" nhưng bạn đã chọn \"{b}\". Lưu nét mực vào tệp đã chọn?", "Cette page est « {a} » mais vous avez choisi « {b} ». Enregistrer l'encre dans le fichier choisi ?", "Esta página é \"{a}\", mas você escolheu \"{b}\". Salvar a tinta no arquivo escolhido?", "هذه الصفحة هي \"{a}\" لكنك اخترت \"{b}\". هل تحفظ الحبر في الملف المختار؟"],
-      "st_no_ink_block": ["That file has no ink block. Paste the overlay snippet into it first.", "Ese archivo no tiene bloque de tinta. Primero pega en él el código de OverBoard.", "该文件没有笔迹区块。请先把 OverBoard 代码粘贴进去。", "Walang ink block ang file na iyan. I-paste muna roon ang OverBoard snippet.", "Tệp đó không có khối nét mực. Hãy dán đoạn mã OverBoard vào trước.", "Ce fichier n'a pas de bloc d'encre. Collez-y d'abord le code d'OverBoard.", "Esse arquivo não tem bloco de tinta. Cole o código do OverBoard nele primeiro.", "هذا الملف لا يحتوي على كتلة الحبر. الصق شيفرة OverBoard فيه أولًا."],
+      "st_no_ink_block": ["That file doesn't have OverBoard in it, so it can't keep ink. Drop it on the OverBoard app first to make a board copy.", "Ese archivo no tiene OverBoard, así que no puede guardar tinta. Primero suéltalo en la app de OverBoard para hacer una copia para la pizarra.", "该文件里没有 OverBoard，无法保存笔迹。请先把它拖到 OverBoard 应用里，生成一份白板副本。", "Walang OverBoard ang file na iyan, kaya hindi ito makakapag-save ng tinta. I-drop muna ito sa OverBoard app para gumawa ng kopya para sa board.", "Tệp đó không có OverBoard nên không lưu được nét mực. Hãy thả nó vào ứng dụng OverBoard trước để tạo bản dùng trên bảng.", "Ce fichier ne contient pas OverBoard, il ne peut donc pas garder l'encre. Déposez-le d'abord sur l'app OverBoard pour en faire une copie pour le tableau.", "Esse arquivo não tem o OverBoard, então não guarda tinta. Primeiro solte-o no app OverBoard para fazer uma cópia para a lousa.", "هذا الملف لا يحتوي على OverBoard، لذا لا يمكنه حفظ الحبر. اسحبه أولًا إلى تطبيق OverBoard لإنشاء نسخة للسبورة."],
       "st_tap_allow": ["{p} · tap Save ink into file to allow writing", "{p} · toca Guardar tinta en el archivo para permitir escribir", "{p} · 点按“把笔迹保存到文件”以允许写入", "{p} · i-tap ang I-save ang tinta sa file para payagang magsulat", "{p} · chạm Lưu nét mực vào tệp để cho phép ghi", "{p} · touchez Enregistrer l'encre dans le fichier pour autoriser l'écriture", "{p} · toque em Salvar tinta no arquivo para permitir gravar", "{p} · اضغط «حفظ الحبر في الملف» للسماح بالكتابة"],
       "st_linked_no_block": ["Linked file has no ink block", "El archivo vinculado no tiene bloque de tinta", "关联文件没有笔迹区块", "Walang ink block ang naka-link na file", "Tệp liên kết không có khối nét mực", "Le fichier lié n'a pas de bloc d'encre", "O arquivo vinculado não tem bloco de tinta", "الملف المرتبط لا يحتوي على كتلة الحبر"],
       "st_saved_to": ["{p} · saved to {f} {t}", "{p} · guardado en {f} {t}", "{p} · 已保存到 {f} {t}", "{p} · na-save sa {f} {t}", "{p} · đã lưu vào {f} {t}", "{p} · enregistré dans {f} {t}", "{p} · salvo em {f} {t}", "{p} · حُفظ في {f} {t}"],
@@ -2226,12 +2226,13 @@
   async function linkFile(){
     var hs = await window.showOpenFilePicker({ types: [{ description: 'This worksheet (.html)', accept: { 'text/html': ['.html', '.htm'] } }] });
     var h = hs[0], base = decodeURIComponent(location.pathname.split('/').pop());
+    // a file without OverBoard in it has nowhere to keep ink: say so before the browser asks to edit it
+    var txt = await (await h.getFile()).text();
+    if (injectInk(txt, '{}') === null) { setStatus(tr('st_no_ink_block')); return 'none'; }
     // ask to write right away, while the tap that opened the file window still counts: in Chrome, our question
     // below uses it up, and then the browser refuses without asking
     try { if ((await h.queryPermission({ mode: 'readwrite' })) !== 'granted') await h.requestPermission({ mode: 'readwrite' }); } catch(e){}
     if (base && h.name !== base && !confirm(tr('confirm_other_file', { a: base, b: h.name }))) return false;
-    var txt = await (await h.getFile()).text();
-    if (injectInk(txt, '{}') === null) { setStatus(tr('st_no_ink_block')); return false; }
     fileHandle = h; idb('readwrite', function(st){ return st.put(h, KEY); });
     return true;
   }
@@ -2256,7 +2257,7 @@
   async function saveFile(forcePick){   // true = ink written into the file, false = not (status line says why), null = picker cancelled
     if (!FSA) { setStatus(tr('st_needs_chrome')); return false; }
     try {
-      if (forcePick || !fileHandle) { if (!(await linkFile())) return null; }
+      if (forcePick || !fileHandle) { var linked = await linkFile(); if (linked === 'none') return false; if (!linked) return null; }   // false: Not saved! on the button
       writeLocal(true);
       for (var i = 0; fileBusy && i < 30; i++) await new Promise(function(r){ setTimeout(r, 100); });   // let an autosave finish first
       return await writeFile(true);
diff --git a/shared/strings.js b/shared/strings.js
index b66a465..b1c537f 100644
--- a/shared/strings.js
+++ b/shared/strings.js
@@ -221,7 +221,7 @@ function obStrings(){
     "saved_flash": ["Saved!", "¡Guardado!", "已保存！", "Na-save!", "Đã lưu!", "Enregistré !", "Salvo!", "تم الحفظ!"],
     "not_saved": ["Not saved!", "¡No se guardó!", "未保存！", "Hindi na-save!", "Chưa lưu!", "Non enregistré !", "Não salvo!", "لم يُحفظ!"],
     "confirm_other_file": ["This page is \"{a}\" but you picked \"{b}\". Save ink into the picked file?", "Esta página es \"{a}\" pero elegiste \"{b}\". ¿Guardar la tinta en el archivo elegido?", "此页面是“{a}”，但你选择了“{b}”。要把笔迹保存到所选文件吗？", "Ang pahinang ito ay \"{a}\" pero \"{b}\" ang pinili mo. I-save ang tinta sa napiling file?", "Trang này là \"{a}\" nhưng bạn đã chọn \"{b}\". Lưu nét mực vào tệp đã chọn?", "Cette page est « {a} » mais vous avez choisi « {b} ». Enregistrer l'encre dans le fichier choisi ?", "Esta página é \"{a}\", mas você escolheu \"{b}\". Salvar a tinta no arquivo escolhido?", "هذه الصفحة هي \"{a}\" لكنك اخترت \"{b}\". هل تحفظ الحبر في الملف المختار؟"],
-    "st_no_ink_block": ["That file has no ink block. Paste the overlay snippet into it first.", "Ese archivo no tiene bloque de tinta. Primero pega en él el código de OverBoard.", "该文件没有笔迹区块。请先把 OverBoard 代码粘贴进去。", "Walang ink block ang file na iyan. I-paste muna roon ang OverBoard snippet.", "Tệp đó không có khối nét mực. Hãy dán đoạn mã OverBoard vào trước.", "Ce fichier n'a pas de bloc d'encre. Collez-y d'abord le code d'OverBoard.", "Esse arquivo não tem bloco de tinta. Cole o código do OverBoard nele primeiro.", "هذا الملف لا يحتوي على كتلة الحبر. الصق شيفرة OverBoard فيه أولًا."],
+    "st_no_ink_block": ["That file doesn't have OverBoard in it, so it can't keep ink. Drop it on the OverBoard app first to make a board copy.", "Ese archivo no tiene OverBoard, así que no puede guardar tinta. Primero suéltalo en la app de OverBoard para hacer una copia para la pizarra.", "该文件里没有 OverBoard，无法保存笔迹。请先把它拖到 OverBoard 应用里，生成一份白板副本。", "Walang OverBoard ang file na iyan, kaya hindi ito makakapag-save ng tinta. I-drop muna ito sa OverBoard app para gumawa ng kopya para sa board.", "Tệp đó không có OverBoard nên không lưu được nét mực. Hãy thả nó vào ứng dụng OverBoard trước để tạo bản dùng trên bảng.", "Ce fichier ne contient pas OverBoard, il ne peut donc pas garder l'encre. Déposez-le d'abord sur l'app OverBoard pour en faire une copie pour le tableau.", "Esse arquivo não tem o OverBoard, então não guarda tinta. Primeiro solte-o no app OverBoard para fazer uma cópia para a lousa.", "هذا الملف لا يحتوي على OverBoard، لذا لا يمكنه حفظ الحبر. اسحبه أولًا إلى تطبيق OverBoard لإنشاء نسخة للسبورة."],
     "st_tap_allow": ["{p} · tap Save ink into file to allow writing", "{p} · toca Guardar tinta en el archivo para permitir escribir", "{p} · 点按“把笔迹保存到文件”以允许写入", "{p} · i-tap ang I-save ang tinta sa file para payagang magsulat", "{p} · chạm Lưu nét mực vào tệp để cho phép ghi", "{p} · touchez Enregistrer l'encre dans le fichier pour autoriser l'écriture", "{p} · toque em Salvar tinta no arquivo para permitir gravar", "{p} · اضغط «حفظ الحبر في الملف» للسماح بالكتابة"],
     "st_linked_no_block": ["Linked file has no ink block", "El archivo vinculado no tiene bloque de tinta", "关联文件没有笔迹区块", "Walang ink block ang naka-link na file", "Tệp liên kết không có khối nét mực", "Le fichier lié n'a pas de bloc d'encre", "O arquivo vinculado não tem bloco de tinta", "الملف المرتبط لا يحتوي على كتلة الحبر"],
     "st_saved_to": ["{p} · saved to {f} {t}", "{p} · guardado en {f} {t}", "{p} · 已保存到 {f} {t}", "{p} · na-save sa {f} {t}", "{p} · đã lưu vào {f} {t}", "{p} · enregistré dans {f} {t}", "{p} · salvo em {f} {t}", "{p} · حُفظ في {f} {t}"],
diff --git a/tests/savefile.spec.js b/tests/savefile.spec.js
index 6c5891b..dd48ba7 100644
--- a/tests/savefile.spec.js
+++ b/tests/savefile.spec.js
@@ -50,9 +50,10 @@ async function saveTap(page) {
   if (await page.locator('#ob-filemenu').isHidden()) await page.click('#ink-bar [data-act="file"]');
   await saveBtn(page).click();
 }
-async function open(page, file) {
+async function open(page, file, again = false) {
   await page.setViewportSize({ width: 1400, height: 900 });
-  await page.goto(url(file)); await overlayReady(page);
+  // again: the file changed on disk; ask past the browser's cache (the test server only knows file times to the second)
+  await page.goto(url(file) + (again ? '?' + Date.now() : '')); await overlayReady(page);
 }
 
 test('save ink into a differently named board copy: the browser asks before our "different file" question', async ({ page }, info) => {
@@ -101,8 +102,24 @@ test('ink written into a board copy shows, even if this browser used that copy m
   // another browser (Edge) wrote ink drawn an hour ago into this file, just now
   const now = Date.now(), stroke = { c: '#111', w: 3, e: 0, p: [100, 100, 300, 100] };
   fs.writeFileSync(clean, withInk(DEMO, { v: 2, t: now - 3600e3, w: now, active: 'P1', periods: { P1: [stroke], P2: [], P3: [], P4: [] } }));
-  await open(page, clean);
+  await open(page, clean, true);
   await expect(page.locator('#ink-status')).toContainText('ink loaded from file');
   await page.click('#ink-bar [data-act="undo"]');   // the file's ink is what's on screen: Undo takes its line away
   await expect(page.locator('#ink-bar [data-act="redo"]')).toBeEnabled();
 });
+
+test('a file without OverBoard in it: Not saved!, said plainly, and the browser never asks to edit it', async ({ page }, info) => {
+  const inked = info.outputPath('pet_board.html');
+  fs.writeFileSync(inked, DEMO);
+  const plain = '<html><body><div class="page">Plain worksheet</div></body></html>';
+  await fakePicker(page, 'pet.html', plain);
+  await open(page, inked);
+  await draw(page);
+  page.on('dialog', (d) => d.accept());
+  await saveTap(page);
+  await saveTap(page);
+  await expect(saveBtn(page)).toHaveText('Not saved!');
+  await expect(page.locator('#ink-status')).toContainText("doesn't have OverBoard in it");
+  expect(await page.evaluate(() => window.__asked)).toBe(0);
+  expect(await page.evaluate(() => window.__file)).toBe(plain);   // untouched
+});