If you can create folders under Program Files without seeing a UAC prompt then that means either UAC is disabled or Opus is running elevated. (Or the Program Files permissions are messed up.)
If Opus is running elevated then that would explain why the recovery partition drive-letter is showing in Opus but not elsewhere. Elevated processes will potentially see a different set of drives to normal ones. (One of several reasons not to run Opus elevated.)
Assuming UAC is turned on, see the How to turn off "Run as Administrator" section of Why not to run Opus as Administrator under UAC for advice.