When Everything is running elevated (not as a service) EVERYTHING searches will work, but the likes of EVERYTHING /O (to then the search dialog) and EVERYTHING /O (to open the properties) will not work because certain communication across security boundaries is forbidden. In this case, you can get to those (dialox and properties) via Everything's tray icon.
The purpose (and only purpose) of the Everything service is to allow another Everything.exe to be started without a UAC prompt. This second Everything.exe serves all the aspects of the EVERYTHING command (and makes a tray icon).