Hi Basara thank you very much for your fast answer but you dont understand me, the process is to reduce quantity in "confirm order", not in "checkout" because a person can not confirm order and the product is not selled.
I check out without problem, its in the "confirm order" option, when you get your order id, if i have 5 people giving clic at the same time and i have only one product quantity, all received an order id and all think they bought the product but only one should, becuase in yard sell first in first out. Right now my quantity goes to -4 and i have track stock activated and Stock Checkout No.
Please tell me how can we confirm order but only the first person receive orderid and all 4 receive a "sorry message".
I thing maybe is a paramenter In settings -> All settings. "config_stock_subtract" = off.
Thank you very much for your help. If you want a can share you the link of the site in a private message.