SharePoint 2013 took away the people picker search tool and replaced it with an autocomplete feature. Type a few letters and matching names appear.
The problem is that this only works when you have typed the third letter of the name. With only two letters SharePoint just sits there patiently and does nothing useful.
But there is a way…
Two secrets for two letter names...
- Type the two letters and a space. Name will pop up.
- Type the two letters and a semicolon. Name will be auto completed.
The semicolon trick also works when you have typed enough to uniquely identify a single user or group. In my farm I only have one "Robert". Typing "rob;" automatically finds him. Typing "sale;" finds and adds the "Sales" AD group.