diff --git a/src/main/frontend/diff.cljs b/src/main/frontend/diff.cljs
index c0e15ac32..8523e5350 100644
--- a/src/main/frontend/diff.cljs
+++ b/src/main/frontend/diff.cljs
@@ -9,6 +9,19 @@
   (-> ((gobj/get jsdiff "diffLines") s1 s2)
       bean/->clj))
 
+(defn diff-words
+  [s1 s2]
+  (-> ((gobj/get jsdiff "diffWords") s1 s2)
+      bean/->clj))
+
+(defn removed?
+  [s1 s2]
+  (when (and s1 s2)
+    (let [diff-result (diff-words s1 s2)]
+      (->> diff-result
+           (some :removed)
+           (boolean)))))
+
 ;; (find-position "** hello _w_" "hello w")
 (defn find-position
   [markup text]
diff --git a/src/main/frontend/fs.cljs b/src/main/frontend/fs.cljs
index 5e1dd13a1..62ff9c339 100644
--- a/src/main/frontend/fs.cljs
+++ b/src/main/frontend/fs.cljs
@@ -5,6 +5,7 @@
             [frontend.idb :as idb]
             [promesa.core :as p]
             [goog.object :as gobj]
+            [frontend.diff :as diff]
             ["/frontend/utils" :as utils]))
 
 ;; We need to cache the file handles in the memory so that
@@ -55,7 +56,7 @@
                 (add-nfs-file-handle! handle-path handle)
                 (println "Stored handle: " (str root-handle "/" new-dir)))
               (p/catch (fn [error]
-                         (println "mkdir error: " error)
+                         (println "mkdir error: " error ", dir: " dir)
                          (js/console.error error)))))))
 
     (and dir js/window.pfs)
@@ -140,8 +141,11 @@
            (p/let [local-file (.getFile file-handle)
                    local-content (.text local-file)]
              (if (and local-content old-content
-                        (= (string/trim local-content)
-                           (string/trim old-content))) ; to prevent overwritten
+                      ;; To prevent data loss, it's not enough to just compare using `=`.
+                      ;; Also, we need to benchmark the performance of `diff/diff-words `
+                      (not (diff/removed?
+                            (string/trim local-content)
+                            (string/trim old-content))))
                (utils/writeFile file-handle content)
                (js/alert (str "The file has been modified in your local disk! File path: " path
                               ", save your changes and click the refresh button to reload it."))))
diff --git a/src/main/frontend/handler.cljs b/src/main/frontend/handler.cljs
index 3d31b0b50..9fba71fc1 100644
--- a/src/main/frontend/handler.cljs
+++ b/src/main/frontend/handler.cljs
@@ -104,6 +104,8 @@
                                                                          :repos repos}))))))
                               (store-schema!))
 
+                            (nfs/ask-permission-if-local?)
+
                             (page-handler/init-commands!)
                             (if (seq (:repos me))
                               ;; FIXME: handle error
diff --git a/src/main/frontend/handler/editor.cljs b/src/main/frontend/handler/editor.cljs
index 277040e2b..fe949ab81 100644
--- a/src/main/frontend/handler/editor.cljs
+++ b/src/main/frontend/handler/editor.cljs
@@ -5,6 +5,7 @@
             [frontend.handler.git :as git-handler]
             [frontend.handler.ui :as ui-handler]
             [frontend.handler.repo :as repo-handler]
+            [frontend.handler.file :as file-handler]
             [frontend.handler.notification :as notification]
             [frontend.handler.draw :as draw]
             [frontend.handler.expand :as expand]
@@ -614,6 +615,7 @@
                                  (block/parse-block (assoc block :block/content new-value) format))
                                parse-result)
                              after-blocks (rebuild-after-blocks repo file (:end-pos meta) end-pos)
+                             files [[file-path new-content]]
                              transact-fn (fn []
                                            (repo-handler/transact-react-and-alter-file!
                                             repo
@@ -624,7 +626,7 @@
                                              after-blocks)
                                             {:key :block/insert
                                              :data (map (fn [block] (assoc block :block/page page)) blocks)}
-                                            [[file-path new-content]])
+                                            files)
                                            (state/set-editor-op! nil))]
 
                          ;; Replace with batch transactions
diff --git a/src/main/frontend/handler/repo.cljs b/src/main/frontend/handler/repo.cljs
index 063a55123..fa42686d5 100644
--- a/src/main/frontend/handler/repo.cljs
+++ b/src/main/frontend/handler/repo.cljs
@@ -239,9 +239,9 @@
     (when (seq pages)
       (let [children-tx (mapcat #(db/rebuild-page-blocks-children repo %) pages)]
         (when (seq children-tx)
-          (db/transact! repo children-tx)))))
-  (when (seq files)
-    (file-handler/alter-files repo files)))
+          (db/transact! repo children-tx))))
+    (when (seq files)
+      (file-handler/alter-files repo files))))
 
 (declare push)
 
diff --git a/src/main/frontend/handler/web/nfs.cljs b/src/main/frontend/handler/web/nfs.cljs
index 464ae2c51..520974986 100644
--- a/src/main/frontend/handler/web/nfs.cljs
+++ b/src/main/frontend/handler/web/nfs.cljs
@@ -119,13 +119,22 @@
     (when handle
       (utils/verifyPermission handle true))))
 
-(defn trigger-check! [cb]
-  (let [repo (state/get-current-repo)
-        nfs-repo? (config/local-db? repo)]
-    (if nfs-repo?
-      (p/let [_ (check-directory-permission! repo)]
-        (cb))
-      (cb))))
+(defn ask-permission
+  [repo]
+  (fn [close-fn]
+    [:div
+     [:p.text-gray-700
+      "Grant native filesystem permission for directory: "
+      [:b (config/get-local-dir repo)]]
+     (ui/button
+       "Grant"
+       :on-click (fn []
+                   (check-directory-permission! repo)
+                   (close-fn)))]))
+
+(defn ask-permission-if-local? []
+  (when-let [repo (get-local-repo)]
+    (state/set-modal! (ask-permission repo))))
 
 (defn- compute-diffs
   [old-files new-files]
@@ -205,7 +214,7 @@
                                    (rename-f "modify" modified))]
                         (when (or (and (seq diffs) (seq modified-files))
                                   (seq diffs) ; delete
-)
+                                  )
                           (repo-handler/load-repo-to-db! repo
                                                          {:diffs diffs
                                                           :nfs-files modified-files})))))
@@ -217,8 +226,7 @@
 (defn- refresh!
   [repo]
   (when repo
-    (p/let [_ (check-directory-permission! repo)]
-      (reload-dir! repo))))
+    (reload-dir! repo)))
 
 (defn supported?
   []