diff --git a/openupgrade_scripts/scripts/sms/17.0.3.0/pre-migration.py b/openupgrade_scripts/scripts/sms/17.0.3.0/pre-migration.py
new file mode 100644
index 000000000000..aa7937dc46fa
--- /dev/null
+++ b/openupgrade_scripts/scripts/sms/17.0.3.0/pre-migration.py
@@ -0,0 +1,31 @@
+# Copyright 2026 NuoBiT Solutions - Eric Antones <eantones@nuobit.com>
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+from openupgradelib import openupgrade
+
+
+@openupgrade.migrate()
+def migrate(env, version):
+    """Pre-create sms_sms.uuid filled with one value per row.
+
+    The uuid field (new in 17.0) is declared with a callable default and
+    a unique constraint. Without this script the ORM creates the column
+    during the upgrade and evaluates the default only once, so every
+    pre-existing row receives the same value and the uuid_unique
+    constraint fails to install.
+    """
+    if not openupgrade.column_exists(env.cr, "sms_sms", "uuid"):
+        openupgrade.logged_query(env.cr, "ALTER TABLE sms_sms ADD COLUMN uuid varchar")
+    # Fill missing values and break any duplicate group left by a
+    # previous upgrade run without this script (deterministic per id,
+    # same 32-hex shape as uuid4().hex, idempotent).
+    openupgrade.logged_query(
+        env.cr,
+        """
+        UPDATE sms_sms
+        SET uuid = md5('sms_sms-uuid-' || id::text)
+        WHERE uuid IS NULL
+            OR uuid IN (
+                SELECT uuid FROM sms_sms GROUP BY uuid HAVING count(*) > 1
+            )
+        """,
+    )