I have 2 Exch '10 servers, fully patched, in a DAG which I setup about 3 yrs ago. My problem is with OWA only, if I use Outlook everything works fine. From the OWA client I am able to send email to my cached recipients as well as new addresses just fine. I can open my address book from the owa mailbox page, whatever that main page is called, without issue. I cannot however open my address book when composing a message, new, forward or reply. If I click on the AB icon, the 'TO' button, the 'CC' button the result is the same, the message windows blinks once and then nothing happens. My message is not affected and I get no error messages. This has worked fine for several years, not sure what changed. If I have left out any pertinent info please let me know and I will update asap.