diff --git a/src/chat/chat_core.c b/src/chat/chat_core.c
index 0acb58c5..43d94d59 100644
--- a/src/chat/chat_core.c
+++ b/src/chat/chat_core.c
@@ -279,51 +279,61 @@ int chat_core_is_initialized(struct UTUN_INSTANCE* inst) { return (inst && CC(in
 
 /* ─── chat settings (GUI → uasync) ─── */
 
-void chat_core_set_setting(struct UTUN_INSTANCE* inst, const char* name, const char* value) {
-    chat_setting_set(inst, name, value);
-    if (name && strcmp(name, "group_autoconnect") == 0) chat_core_apply_group_autoconnect(inst);
+int chat_core_set_setting(struct UTUN_INSTANCE* inst, const char* name, const char* value) {
+    int rc = chat_setting_set(inst, name, value);
+    if (!rc && !strcmp(name, "group_autoconnect")) chat_core_apply_group_autoconnect(inst);
+    return rc;
 }
 
 void chat_core_set_setting_trampoline(void* arg) {
     struct chat_setting_arg* a = (struct chat_setting_arg*)arg;
-    const char* name = a->data;
-    const char* value = name + strlen(name) + 1;
-    chat_core_set_setting(a->inst, name, value);
+    if (!a) { DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "chat setting: null request"); return; }
+    const char* end = memchr(a->data, 0, sizeof(a->data));
+    if (!end || end == a->data + sizeof(a->data) - 1 || !memchr(end + 1, 0, sizeof(a->data) - (size_t)(end + 1 - a->data)))
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "chat setting: unterminated name/value request");
+    else chat_core_set_setting(a->inst, a->data, end + 1);
     u_free(arg);
 }
 
 /* ─── per-channel «play sound on new message» ─── */
 
 int chat_core_get_sound_on_message(struct UTUN_INSTANCE* inst, const char* ch_id) {
-    struct chat_core_ctx* cc = CC(inst);
-    if (!cc || !cc->initialized || !ch_id || !ch_id[0]) return 1;
+    struct chat_core_ctx* cc = inst ? CC(inst) : NULL;
+    if (!cc || !cc->initialized || !cc->db || !chat_channel_id(ch_id)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "sound setting: invalid read context/channel"); return -1;
+    }
     char key[128]; snprintf(key, sizeof(key), "ch_%s_sound_on_message", ch_id);
     sqlite3_stmt* st = NULL;
-    if (sqlite3_prepare_v2(cc->db, "SELECT value FROM ui_state WHERE key=?", -1, &st, NULL) != SQLITE_OK) return 1;
-    sqlite3_bind_text(st, 1, key, -1, SQLITE_STATIC);
-    int on = 1;
-    if (sqlite3_step(st) == SQLITE_ROW) {
+    int rc = sqlite3_prepare_v2(cc->db, "SELECT value FROM ui_state WHERE key=?", -1, &st, NULL), on = 1;
+    if (rc == SQLITE_OK) rc = sqlite3_bind_text(st, 1, key, -1, SQLITE_STATIC);
+    if (rc == SQLITE_OK) rc = sqlite3_step(st);
+    if (rc == SQLITE_ROW) {
         const char* v = (const char*)sqlite3_column_text(st, 0);
-        if (v) on = atoi(v) != 0;
+        if (sqlite3_column_type(st, 0) != SQLITE_TEXT || sqlite3_column_bytes(st, 0) != 1 || !v || (*v != '0' && *v != '1')) rc = SQLITE_CORRUPT;
+        else on = *v == '1';
+    }
+    int final = sqlite3_finalize(st);
+    if ((rc != SQLITE_ROW && rc != SQLITE_DONE) || final != SQLITE_OK) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "sound setting: read ch=%s rc=%d finalize=%d: %s", ch_id, rc, final, sqlite3_errmsg(cc->db)); return -1;
     }
-    sqlite3_finalize(st);
     return on;
 }
 
-void chat_core_set_sound_on_message(struct UTUN_INSTANCE* inst, const char* ch_id, int on) {
-    struct chat_core_ctx* cc = CC(inst);
-    if (!cc || !cc->initialized || !ch_id || !ch_id[0]) return;
+int chat_core_set_sound_on_message(struct UTUN_INSTANCE* inst, const char* ch_id, int on) {
+    if (!chat_channel_id(ch_id)) { DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "sound setting: invalid channel"); return -1; }
     char key[128]; snprintf(key, sizeof(key), "ch_%s_sound_on_message", ch_id);
     char val[2]; snprintf(val, sizeof(val), "%d", on ? 1 : 0);
-    chat_core_save_ui_state(inst, key, val);
+    if (chat_core_save_ui_state(inst, key, val)) return -1;
     DEBUG_INFO(DEBUG_CATEGORY_CHAT_SYNC, "%s: sound_on_message ch=%s = %d", CC_ID, ch_id, on ? 1 : 0);
     chat_sync_broadcast_sound_setting(inst, ch_id, on ? 1 : 0);
+    return 0;
 }
 
 void chat_core_set_sound_on_message_trampoline(void* arg) {
     struct chat_sound_arg* a = (struct chat_sound_arg*)arg;
-    if (!a) return;
-    chat_core_set_sound_on_message(a->inst, a->ch_id, a->on);
+    if (!a) { DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "sound setting: null request"); return; }
+    if (!memchr(a->ch_id, 0, sizeof(a->ch_id))) DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "sound setting: unterminated channel request");
+    else chat_core_set_sound_on_message(a->inst, a->ch_id, a->on);
     u_free(arg);
 }
 
diff --git a/src/chat/chat_core.h b/src/chat/chat_core.h
index 364b32d5..fcf68327 100644
--- a/src/chat/chat_core.h
+++ b/src/chat/chat_core.h
@@ -190,14 +190,18 @@ void chat_core_sync_my_addresses(struct UTUN_INSTANCE* inst);
  * Адреса обновляются отдельно через topo_node; подпись member-блока их не содержит. */
 void chat_core_update_my_member(struct UTUN_INSTANCE* inst);
 
-// Сохранение key-value в ui_state (вызывается из uasync-потока)
-void chat_core_save_ui_state(struct UTUN_INSTANCE* inst, const char* key, const char* value);
+/* Сохранить key/value в uasync:0 — committed/no-op,-1 — отказ;key непустой,value допускает пустую строку.
+ * Собственная транзакция проверяет все SQL-этапы;внешняя запрещена,no-op не вызывает commit hook.
+ * Ошибка сохраняет прежнее значение;unrecovered rollback запрашивает owner stop/DB close. */
+int chat_core_save_ui_state(struct UTUN_INSTANCE* inst, const char* key, const char* value);
 
 /* Per-channel «play sound on new message» (ui_state: ch_<id>_sound_on_message, default 1=on).
- * set — сохраняет и рассылает пирам через chat_sync (троттлинг db_sync на сервере). */
+ * get возвращает0/1,-1 при ошибке;отсутствие записи —1. set возвращает0/-1,
+ * после собственного commit/no-op рассылает желаемое значение через chat_sync best effort.
+ * SQL-отказ не рассылается,идентичный повтор повторяет доставку. ch_id — канонический ID канала. */
 int  chat_core_get_sound_on_message(struct UTUN_INSTANCE* inst, const char* ch_id);
 
-void chat_core_set_sound_on_message(struct UTUN_INSTANCE* inst, const char* ch_id, int on);
+int chat_core_set_sound_on_message(struct UTUN_INSTANCE* inst, const char* ch_id, int on);
 
 struct chat_sound_arg { struct UTUN_INSTANCE* inst; char ch_id[64]; int on; };
 void chat_core_set_sound_on_message_trampoline(void* arg);
@@ -206,7 +210,7 @@ struct save_ui_state_arg { struct UTUN_INSTANCE* inst; char data[1024]; };
 void chat_core_save_ui_state_trampoline(void* arg);
 
 // Установка chat-настройки (name=value) через chat_setting API (GUI → uasync)
-void chat_core_set_setting(struct UTUN_INSTANCE* inst, const char* name, const char* value);
+int chat_core_set_setting(struct UTUN_INSTANCE* inst, const char* name, const char* value);
 
 struct chat_setting_arg { struct UTUN_INSTANCE* inst; char data[256]; };
 void chat_core_set_setting_trampoline(void* arg);
diff --git a/src/chat/chat_profile.c b/src/chat/chat_profile.c
index 496d491d..ff2d3b76 100644
--- a/src/chat/chat_profile.c
+++ b/src/chat/chat_profile.c
@@ -375,24 +375,60 @@ void chat_core_sync_my_addresses(struct UTUN_INSTANCE* inst) {
     chat_core_update_my_member(inst);
 }
 
-void chat_core_save_ui_state(struct UTUN_INSTANCE* inst, const char* key, const char* value) {
-    struct chat_core_ctx* cc = CC(inst);
-    if (!cc || !cc->initialized || !key || !value) return;
-    sqlite3_stmt* st = NULL;
-    sqlite3_prepare_v2(cc->db,
-        "INSERT OR REPLACE INTO ui_state(key, value) VALUES(?, ?)", -1, &st, NULL);
-    if (st) {
-        sqlite3_bind_text(st, 1, key, -1, SQLITE_STATIC);
-        sqlite3_bind_text(st, 2, value, -1, SQLITE_STATIC);
-        sqlite3_step(st); sqlite3_finalize(st);
+int chat_core_save_ui_state(struct UTUN_INSTANCE* inst, const char* key, const char* value) {
+    struct chat_core_ctx* cc = inst ? CC(inst) : NULL;
+    if (!cc || !cc->initialized || !cc->db || !key || !key[0] || !value || strlen(key) > INT_MAX || strlen(value) > INT_MAX ||
+        !sqlite3_get_autocommit(cc->db)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: invalid context/key/value or outer transaction"); return -1;
     }
+    int rc = sqlite3_exec(cc->db, "BEGIN IMMEDIATE /* ui_state */", NULL, NULL, NULL);
+    if (rc != SQLITE_OK) { DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: begin rc=%d: %s", rc, sqlite3_errmsg(cc->db)); return -1; }
+    sqlite3_stmt* st = NULL; const char* stage = "prepare read"; int result = -1, same = 0;
+    rc = sqlite3_prepare_v2(cc->db, "SELECT value FROM ui_state WHERE key=?", -1, &st, NULL);
+    if (rc == SQLITE_OK) { stage = "bind read"; rc = sqlite3_bind_text(st, 1, key, -1, SQLITE_STATIC); }
+    if (rc == SQLITE_OK) { stage = "step read"; rc = sqlite3_step(st); }
+    if (rc == SQLITE_ROW) {
+        int type = sqlite3_column_type(st, 0), bytes = sqlite3_column_bytes(st, 0);
+        const char* text = (const char*)sqlite3_column_text(st, 0);
+        if (type != SQLITE_NULL && (type != SQLITE_TEXT || !text || strlen(text) != (size_t)bytes)) {
+            stage = "stored value"; rc = SQLITE_CORRUPT; goto error;
+        }
+        same = text && !strcmp(text, value);
+    } else if (rc != SQLITE_DONE) goto error;
+    stage = "finalize read"; rc = sqlite3_finalize(st); st = NULL; if (rc != SQLITE_OK) goto error;
+    if (same) { DEBUG_DEBUG(DEBUG_CATEGORY_CHAT, "UI state: unchanged key=%s", key); result = 0; goto done; }
+    stage = "prepare write";
+    rc = sqlite3_prepare_v2(cc->db, "INSERT INTO ui_state(key,value) VALUES(?1,?2) ON CONFLICT(key) DO UPDATE SET value=excluded.value", -1, &st, NULL);
+    if (rc == SQLITE_OK) { stage = "bind key"; rc = sqlite3_bind_text(st, 1, key, -1, SQLITE_STATIC); }
+    if (rc == SQLITE_OK) { stage = "bind value"; rc = sqlite3_bind_text(st, 2, value, -1, SQLITE_STATIC); }
+    if (rc == SQLITE_OK) { stage = "step write"; rc = sqlite3_step(st); }
+    if (rc != SQLITE_DONE) goto error;
+    if (sqlite3_changes(cc->db) != 1) { stage = "changes != 1"; rc = SQLITE_CONSTRAINT; goto error; }
+    stage = "finalize write"; rc = sqlite3_finalize(st); st = NULL; if (rc != SQLITE_OK) goto error;
+    stage = "commit"; rc = sqlite3_exec(cc->db, "COMMIT /* ui_state */", NULL, NULL, NULL); if (rc != SQLITE_OK) goto error;
+    DEBUG_DEBUG(DEBUG_CATEGORY_CHAT, "UI state: committed key=%s bytes=%zu", key, strlen(value)); return 0;
+error:
+    DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: key=%s stage=%s rc=%d: %s", key, stage, rc, sqlite3_errmsg(cc->db));
+done:
+    rc = sqlite3_finalize(st);
+    if (rc != SQLITE_OK) DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: cleanup finalize rc=%d", rc);
+    if (!sqlite3_get_autocommit(cc->db)) {
+        rc = sqlite3_exec(cc->db, "ROLLBACK", NULL, NULL, NULL);
+        if (rc != SQLITE_OK) { DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: rollback rc=%d: %s", rc, sqlite3_errmsg(cc->db)); result = -1; }
+        if (!sqlite3_get_autocommit(cc->db)) {
+            DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: transaction remains open;requesting owner stop/DB close");
+            utun_instance_stop(inst); result = -1;
+        }
+    }
+    return result;
 }
 
 void chat_core_save_ui_state_trampoline(void* arg) {
     struct save_ui_state_arg* a = (struct save_ui_state_arg*)arg;
-    if (!a) return;
-    const char* key = a->data;
-    const char* value = key + strlen(key) + 1;
-    chat_core_save_ui_state(a->inst, key, value);
+    if (!a) { DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: null request"); return; }
+    const char* end = memchr(a->data, 0, sizeof(a->data));
+    if (!end || end == a->data + sizeof(a->data) - 1 || !memchr(end + 1, 0, sizeof(a->data) - (size_t)(end + 1 - a->data)))
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT, "UI state: unterminated key/value request");
+    else chat_core_save_ui_state(a->inst, a->data, end + 1);
     u_free(arg);
 }