Need help figuring out why virtualbox guest will not start back up

I am new to virtualbox, and yesterday I set up a new machine, but it was interrupted during it's shutdown, and now when I try to start it up I get this error. Any help would be appreciated.

Failed to open a session for the virtual machine TestServer.

Value not found. (VERR_CFGM_VALUE_NOT_FOUND).

Result Code: E_FAIL (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}