Hi @Alistair Trout,
Thank you for posting in this community.
How did you add that user, through AD or through User Profile Service? The problem seems to be that the user profile is not synchronized.
I suggest you do a full synchronization of user profiles:
- On the SharePoint Central Administration website, in the Application Management section, click Manage service applications.
- On the Manage Service Applications page, click the link for the User Profile service application.
- On the Manage Profile Service page, in the Synchronization section, click Start Profile Synchronization.
- On the Start Profile Synchronization page, select Start Full Synchronization to synchronize all profiles.
- Click OK.
You can refresh the Manage Profile Service page to view the profile synchronization status.
After the synchronization is complete, please clear your browser cache or use your browser privacy mode to recheck if the problem still exists.
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