When I play my MKV file test in WMC on my computer works perfectly. When I open WMC on my Xbox, I can see my test file with thumbnail images of MKV and everything. When attempting to open the file on my xbox, however, I get a message saying something along the lines of: Video Error Files needed to display video are not installed or not functioning properly. Restart Windows Media Center or restart the computer. These files are played nearby on the Media Center PC from side to side Windows Media Center and Windows Media Player without problems. Then how can I configure Xbox 360 as windows media extender.