diff --git a/htdocs/install/mysql/migration/5.0.0-6.0.0.sql b/htdocs/install/mysql/migration/5.0.0-6.0.0.sql
index 9a3ab73d133..bf28e6a3db6 100644
--- a/htdocs/install/mysql/migration/5.0.0-6.0.0.sql
+++ b/htdocs/install/mysql/migration/5.0.0-6.0.0.sql
@@ -212,7 +212,9 @@ ALTER TABLE llx_default_values ADD UNIQUE INDEX uk_default_values(type, entity,
 ALTER TABLE llx_supplier_proposaldet ADD INDEX idx_supplier_proposaldet_fk_supplier_proposal (fk_supplier_proposal);
 ALTER TABLE llx_supplier_proposaldet ADD INDEX idx_supplier_proposaldet_fk_product (fk_product);
 
+UPDATE llx_supplier_proposaldet SET fk_unit = NULL where fk_unit not in (SELECT rowid from llx_c_units);
 ALTER TABLE llx_supplier_proposaldet ADD CONSTRAINT fk_supplier_proposaldet_fk_unit FOREIGN KEY (fk_unit) REFERENCES llx_c_units (rowid);
+
 ALTER TABLE llx_supplier_proposaldet ADD CONSTRAINT fk_supplier_proposaldet_fk_supplier_proposal FOREIGN KEY (fk_supplier_proposal) REFERENCES llx_supplier_proposal (rowid);
 
 -- NEW inventory module