I have a number of distribution lists on Outlook 2007. A few months ago they stopped working. I receive an "unexpected error" when I hit the send button. It does not matter if it is an old list or a newly created one. I also cannot use the + to expand the list and see the names. I also get an error: "cannot perform the requested operation. The command selected is not valid for this recipient. The operation failed." I have searched various helps and forums and found a few other people with this problem, but no satisfactory answers. I have put hours into this, as I can no longer do my job and will have to quit using Outlook, even though I [otherwise] like it. I cannot even find the threads/questions I was following before. I am desperate, even put in my product code to get help from MS, but it says my code is invalid even though I have a perfectly expensive and legit version of Office on my computer. I cannot use distribution lists at all, and even the send function doesn't always work (happened around the same time). I think these problems have to be related, but I don't know what to do. I am running Windows 7, Outlook 2007. I have installed the most recent fix and have even uninstalled and reinstalled Office in an attempt to fix the problem. It just comes back as broken as before. Any ideas??