We have half of our computers unable to reliably update their NK2 files. We are using XP with Outlook 2003, and Server 2003 Std with Exchange 2007.
In some cases the NK2 files will update for a few weeks, or a few days, or only once. We have taken the following steps:
1. deleted and/or renamed the NK2 file to have a new one created
2. unchecked the nickname box in Outlook, restarted, rechecked the box to "restart" the NK2 writing
3. created a new Outlook profile with a different name on the affected computers
The problem will then go a way for a short period of time and then occur again.