Microsoft admits in its Newsgroup that DirectX 9 might cause Windows Messenger not to work properly on some setups. They also mentioned that this is being looked into and promising a solution to this issue soon. Qba73 were able to provide us with a quote from Jonathan Kay, Windows MVP:
"It's being looked into -- hopefully a solution will be available soon. In the meantime, I don't believe any games exclusively require DirectX 9 to be installed (considering it was just released) -- you can easily use System Restore to restore back to before you installed it (Start, Help & Support, 'Undo changes to my computer using System Restore') and Windows Messenger should once again work properly."
