Just installed ADE. I tried to compile a airport project, & get the UAC error box. I did all the stuff necessary including disabling UAC, that didn't help. I finally disabled it in the registry, still no joy. Any help getting past this appreciated.
Are you actually sure the folder is there. This message is being generated because ADE cannot write to that folder. The message will be the same if it is there and UAC is locking it or if it is not there at all. By default P3D v3 does not have an Addon Scenery folder. LM are trying to get us all to stop writing to folders inside the sim structure. If you really want to use that folder then you will need to add it as a new scenery area yourself