Thread: Primary key keeps disappearing allowing unwanted duplicates

Hi there. I have set up a simple database which is shared between a few of us. However the primary key field in one of the tables is allowing duplicates.

I am certain no one is actually changing this in design view, and sometimes when I go into design view, the primary key icon is missing!

HAve any of you helpful people had any experience of this? I'm a very basic Access user so please be gentle.

Thank you