Caution Installing Apps via Windows Terminal Service (aka Remote Desktop Connection)

You may notice on some Windows servers, when you install new application remotely (via a Terminal Service client), your previously installed applications may loose their install information (e.g., wiped out) that when upgrading them, upgrade program is not aware of their previously installed status.

First, you need to be aware that Terminal Services comes in two modes. Terminal Services is Windows' way of allowing multiple logons to a single machine. It handles this by automatically having each user write files to a "user-specific" copy of the files so that they don't conflict with each other. This is normally fine, except when a product is being installed, in which case you want the product installed in the "OS" copy of the files and not just for that user. Windows allows you to do this by setting the mode to INSTALL mode instead of EXECUTE mode.

In general, system administrators need know that these two modes exist and switch to INSTALL mode themselves before they start running installation programs. A better solution, though, is to to install in a mode called "remote administration". When installed this way, the "EXECUTE" vs "INSTALL" modes no longer applies. That means, the licensing needs to be "Remote Desktop for Administration" vs "Per User" in the non-administrative mode (see screen).

C:\>change user /query
Application EXECUTE mode is enabled.
Install mode does not apply to a Terminal server configured for remote administration.
(notes: that means it is installed for remote administration.)
C:\>change user /query
Application EXECUTE mode is enabled.
(notes: this means it is installed for Per User. You must switch to INSTALL mode 
if you want to install software remotely!)