If you're trying to install a "Prepare3D Compatible" add-on into P3Dv2, you may find that it either doesn't seem to install correctly, or that it DOES appear to install correctly, but you can't configure the add-on (you get errors, or the config data you enter doesn't seem to "stick" when you click 'OK'), this is very likely because the add-on is expecting to store its configuration data very specifically in the "C:\Users\<your user name>\AppData\Roaming\LockheedMartin\Prepar3D" folder -- which isn't there.
There is a very simple workaround for this: use a symbolic link. Some of you may not realize that Windows 7 (and 8) even *have* symbolic links, but they do. To fix this specific issue, do the following:
- Launch a cmd shell as administrator
- cd "%appdata%\Lockheed Martin"
- mklink /d 'Prepar3D' 'Prepar3D v2' (this creates the symlink -- changing to the 'Prepar3D' folder will actually put you in the 'Prepar3D v2' folder)
One note: if you still have Prepar3D v1.4 (or earlier) installed, the necessary path to an %AppData% folder will already exist, and the add-ons will probably both install correctly and work -- but the .ini files won't be where you expect. If you decided you want to hand-edit a .ini file and looked in the 'Prepar3D v2' folder -- which is where you expect to find the .ini files -- you won't see them (unless your add-on is, er, already prepared to correctly handle Prepar3D v2). Instead, the .ini files in the old 'Prepar3D' legacy folder will be the ones your add-on is reading and writing. This is fine -- but be aware if you decide to uninstall P3D v1.4!
-M.