diff --git a/add_missing_columns.sh b/add_missing_columns.sh
index c7b1823..0dcdfa0 100755
--- a/add_missing_columns.sh
+++ b/add_missing_columns.sh
@@ -437,7 +437,7 @@ echo ""
 # -
 echononl "   Backup MySQL database '$DATABASE_NAME'.."
 if [[ "$DATABASE_TYPE" = 'mysql' ]]; then
-   mysqldump $MYSQL_CREDENTIALS --opt $DATABASE_NAME > \
+   mysqldump $MYSQL_CREDENTIALS --single-transaction $DATABASE_NAME > \
       ${WEB_BASE_DIR}/${DATABASE_NAME}-v${CURRENT_VERSION}.${backup_date}.sql 2> $log_file
    if [[ $? -eq 0 ]]; then
       echo_ok
diff --git a/update_nextcloud.sh b/update_nextcloud.sh
index e41a188..bc71531 100755
--- a/update_nextcloud.sh
+++ b/update_nextcloud.sh
@@ -576,7 +576,8 @@ echo ""
 # -
 echononl "   Backup MySQL database '$DATABASE_NAME'.."
 if [[ "$DATABASE_TYPE" = 'mysql' ]]; then
-   mysqldump $MYSQL_CREDENTIALS --opt $DATABASE_NAME > \
+   #mysqldump $MYSQL_CREDENTIALS --opt $DATABASE_NAME > \
+   mysqldump $MYSQL_CREDENTIALS --single-transaction $DATABASE_NAME > \
       ${WEB_BASE_DIR}/${DATABASE_NAME}-v${PRIOR_VERSION}.${backup_date}.sql 2> $log_file
    if [[ $? -eq 0 ]]; then
       echo_ok