After checking the P3D master compatibility list, it should install with no issues.
Of course it does...
"You must enter full path with drive letter; for example
C:\APP
or UNC path in the form:
\\server\share"
So I tried the manual method of selecting my P3D drive and click "Ok" and I get a message displaying "FSX not found"
Those messages seems to indicate that you either have:
1) Tried to run the installer from a network drive. If yes, don't do it. Run it from a regular disk.
OR
2) Your registry keys for P3D might be wrong and/or corrupted and/or pointing to the wrong folder. The most likely cause for this, is that you use or have used the P3D Migration Tool, so your registry keys are messed up. When installing a PROPER P3D installer, the P3D Migration Tool MUST be off. And we had report from users that had their P3D registry keys messed up because of the tool not properly disabled/uninstalled or because of bugs in old versions of it.
Check your registry key for P3D, be sure is pointing to the folder P3D is installed into. Use the REGEDIT default utility, and go to:
HKEY_CURRENT_USER\Software\Lockheed Martin\Prepar3D v2\AppPath
And check the path is the correct one where P3D is installed now.