One of our employees is using a laptop with Windows 7 and Outlook 2010 (we use Exchange 2010 SP3). He recently reported that the auto-complete function in Outlook, when you start to type in the name of a recipient and a list appears, stopped working. I followed the steps in a Technet article that had you disable cached mode, close Outlook, then rename the "roamcache" folder, and then open Outlook, enable cached mode, close it and reopen it. This procedure seemed to clear the auto-complete list, which I then populated by creating a draft email addressed to every contact in his addressbook (this caused the list of email addresses to appear as desired and as usual).
However, today the employee let me know that auto-complete is not listing the email addresses when he starts typing in a name. All that has happened, between the fix and test I performed, is the employee turned the laptop off and on again and reopened Outlook. Any ideas on what to check or correct to get this resolved would be appreciated.