diff --git a/htdocs/install/mysql/migration/15.0.0-16.0.0.sql b/htdocs/install/mysql/migration/15.0.0-16.0.0.sql
index f4b7689d6df..ac8fdab8c97 100644
--- a/htdocs/install/mysql/migration/15.0.0-16.0.0.sql
+++ b/htdocs/install/mysql/migration/15.0.0-16.0.0.sql
@@ -738,6 +738,8 @@ ALTER TABLE llx_expedition ADD COLUMN billed smallint    DEFAULT 0;
 
 ALTER TABLE llx_loan_schedule ADD UNIQUE INDEX uk_loan_schedule_ref (fk_loan, datep);
 
+ALTER TABLE llx_overwrite_trans DROP INDEX uk_overwrite_trans;
+ALTER TABLE llx_overwrite_trans ADD UNIQUE INDEX uk_overwrite_trans(lang, transkey, entity);
 
 
 -- Bank Thirdparty
diff --git a/htdocs/install/mysql/tables/llx_overwrite_trans.key.sql b/htdocs/install/mysql/tables/llx_overwrite_trans.key.sql
index 617036e66ee..41493d43f9e 100644
--- a/htdocs/install/mysql/tables/llx_overwrite_trans.key.sql
+++ b/htdocs/install/mysql/tables/llx_overwrite_trans.key.sql
@@ -17,5 +17,5 @@
 -- ===========================================================================
 
 
-ALTER TABLE llx_overwrite_trans ADD UNIQUE INDEX uk_overwrite_trans(lang, transkey);
+ALTER TABLE llx_overwrite_trans ADD UNIQUE INDEX uk_overwrite_trans(lang, transkey, entity);