People Picker Field on Datasheet View Empty

When working with a task list in datasheet view, the people picker drop-list should contain the users that are in the site’s user information list.   Occasionally, I have come across the scenario where this list is empty and only shows “(All)”, making the list useless.

1. To resolve this issue, simply open the list in SharePoint Designer.  Select the list from the Lists and Libraries section. This will display the list settings page in SPD.
2. Click Edit List Columns
   
3. Click the person or group column to display the column editor.  Simply click OK.
4. Click the Save icon in the title bar of SPD to save the list.
5. Refresh the datasheet view of the list in SharePoint and now you should have people/groups to select from.