diff --git a/api.php b/api.php
index 8b424a2..14b007f 100644
--- a/api.php
+++ b/api.php
@@ -2906,8 +2906,9 @@ switch ($action) {
         $threadedCount = 0;
         $errors = [];
 
-        // Collect all existing message IDs for duplicate detection
-        $existingMsgIds = [];
+        // Collect all previously fetched message IDs (persists even after ticket deletion)
+        $existingMsgIds = dbGetFetchedMessageIds($companyId);
+        // Also include message IDs from current tickets (for backward compatibility)
         foreach ($tickets as $t) {
             if ($t['message_id']) $existingMsgIds[$t['message_id']] = true;
             foreach ($t['messages'] ?? [] as $m) {
@@ -3016,7 +3017,7 @@ switch ($action) {
                     ];
 
                     // Apply auto-rules
-                    $toAddresses = implode(' ', $email['to'] ?? []);
+                    $toAddresses = $email['to'] ?? '';
                     foreach ($rules as $rule) {
                         if (empty($rule['enabled'])) continue;
                         $match = true;
@@ -3094,7 +3095,11 @@ switch ($action) {
                     $newCount++;
                 }
 
-                if ($email['message_id']) $existingMsgIds[$email['message_id']] = true;
+                // Merkitse haetuksi pysyvästi
+                if ($email['message_id']) {
+                    dbMarkMessageIdFetched($companyId, $email['message_id']);
+                    $existingMsgIds[$email['message_id']] = true;
+                }
             }
         }
 
diff --git a/db.php b/db.php
index 410c02c..7584667 100644
--- a/db.php
+++ b/db.php
@@ -358,6 +358,16 @@ function initDatabase(): void {
             INDEX idx_company (company_id)
         ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4",
 
+        "CREATE TABLE IF NOT EXISTS fetched_message_ids (
+            id INT AUTO_INCREMENT PRIMARY KEY,
+            company_id VARCHAR(50) NOT NULL,
+            message_id VARCHAR(512) NOT NULL,
+            fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+            UNIQUE KEY uk_company_msgid (company_id, message_id),
+            FOREIGN KEY (company_id) REFERENCES companies(id) ON DELETE CASCADE,
+            INDEX idx_company (company_id)
+        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4",
+
         "CREATE TABLE IF NOT EXISTS customer_priority_emails (
             id INT AUTO_INCREMENT PRIMARY KEY,
             company_id VARCHAR(50) NOT NULL,
@@ -1640,6 +1650,22 @@ function dbDeleteTicketType(string $companyId, string $value): void {
     _dbExecute("DELETE FROM ticket_types WHERE company_id = ? AND value = ?", [$companyId, $value]);
 }
 
+// ==================== HAETUT MESSAGE-ID:T (duplikaattien esto) ====================
+
+function dbGetFetchedMessageIds(string $companyId): array {
+    $rows = _dbFetchAll("SELECT message_id FROM fetched_message_ids WHERE company_id = ?", [$companyId]);
+    $ids = [];
+    foreach ($rows as $r) { $ids[$r['message_id']] = true; }
+    return $ids;
+}
+
+function dbMarkMessageIdFetched(string $companyId, string $messageId): void {
+    if (empty($messageId)) return;
+    try {
+        _dbExecute("INSERT IGNORE INTO fetched_message_ids (company_id, message_id) VALUES (?, ?)", [$companyId, $messageId]);
+    } catch (\Throwable $e) { /* duplicate, ok */ }
+}
+
 // ==================== YRITYKSEN API-ASETUKSET ====================
 
 function dbGetCompanyConfig(string $companyId): array {