Hi Jackolicious, thanks for the reply. We are using the most recent Mac clients. I did submit a support ticket but as you can see I was having trouble adequately describing the problem to differentiate it from the normal questions about tags in shared notebooks so the answer I got didn't help. In the end I used AppCleaner to remove the app, the preference files and all Evernote data from her Mac then reinstalled and resynced her account and she can now add any tag that I have already created.