The global address book in AX has a basic duplicate check feature that you can turn on to avoid entering multiple parties. This is a useful feature to try to avoid clutter if people don’t search before entering a new contact for example. The search capabilities in AX are pretty good but sometime people just don’t use them so you might want to have the system enforce the check. This is a quick walk through where to find setting in AX.

Cheers

Lachlan