I didn't make any upgrades or system changes. I'm just using the local root account, no AD or other authentication integration.
Last night I tried to login to the web client, but couldn't (bad credentials). Some research pointed to the likelihood of the default password I was using expiring. I rebooted into the bash prompt and changed the root password.
I can login to vCenter with the VI Client and my inventory is complete. This works great except for the fact that I can't change any settings relating to a 5.5 VM through the client. I have to use the web interface. I login to the web interface and the inventory is blank.
Most of my searching revolves around authentication or permissions issues, but I have a rather simplistic system. As I stated above, the basic root account, no external authentication. That's not likely it, especially since it works in the standard client. I suspect the web interface somehow separated itself from the inventory service, but wouldn't know where to begin how to fix it nor what log files to look into.