We are having an issue with old Lync pictures appearing in lync clients. These are users that have had their pictures retaken and re-uploaded into the AD database.
At first I thought it was one user's client caching an old photo So I navigated to\%AppData%\..\Local\Microsoft\Office\15.0\Lync\ and renamed the Sip profile to .old
This resolved the issue for some time. Then next time I talked to the user, not only her but others in the company were seeing her old picture.
I compared the AD attribute for thumbnailphoto on both of the domain controllers. They were the same and both the correct photo.
On the Lync management shell I ran get-csclientpolicy, the policy is set to only use photos from AD.
Recently I have noticed that manual deletion of the OAB file and then restart of Lync fixes the issue temporarily but eventually old pictures end up showing in the Lync clients and more users are having an issue as more people have their pictures retaken.
Is there anything else that could be caching/distributing these pictures?