System reports unexpected shutdown when shutdown properly. How to debug/Where to start?

I'm running windows server 2008 R2. When I shutdown my server, it appears to shutdown correctly.

But, when it boots up it prompts me about an unexpected shutdown. I don't have any minidumps and I can't find anything helpful in the event viewer. I do see a Kernel-Power event saying the system shutdown unexpectedly.

That said, if anyone has any suggestions about what to search for in the event viewer, I'm open to giving it a try.

Thanks!