Trying to install MSI app (at least cache it) during lights out.

Workstation is not logged in, but at login prompt. W/S object has
Read rights to MSI install folder.

Get error:

>>Failed to cache application XXXX. Error code was 2.<<

Saw previous thread about W/S needing access to MSI folder.

Question: How will W/S get access if it's not logged in and mapped?