You can contact that software vendor.

You need a password to delete the menu inside. Please look in the Help section and the System Management section. Many of them are written in it.

See if it is an SQL database, find someone who knows SQL, or delete the menu with a statement.

generally used dishes can't be deleted, because the deleted dishes are illegal, and the system can't find the previous information.

if it doesn't work, try to find out that one dish in the software has been stopped, all the dishes have been stopped, and then reset it.

There is another problem. Find the administrator's number, open the system, and then operate, because the administrator's account is the most authoritative and can perform all operations.

See if the software is suitable for your store. If not, buy a new one.

There are too many brands of catering software now. Finding the right one is the most important thing.

if you can't find a software manufacturer, you should also consider the future service, and there will be many problems.