Two user save around the same time and create one row instead of two,


As question above, two users are in row 1 and populating columns A-G, once they are finished save the sheet at nearly the same time (lets say within a minute), instead of queuing their saves and populating one user's information in row 1 and next user in row 2, it instead populated a mix of both in the same row. Any idea's of how to fix this?