I did a search and found the "solution" tot he missing buildings about getting rid of some bglmanx file and some other file, reboot, uninstall scenery, reinstall scenery and so on. That solution did not work.Now when I reinstall the scenery I get a Runtime Error (at 116:2188): Error on Line 51, position 20:Invalid at the top level of the document.
If you got this error, this doesn't have anything to do with the other "missing buildings" problems but, instead, is related to the fact that either your DLL.XML or EXE.XML files were already corrupted or had a syntax error (by the installation of another product or by having edited it by hand), so the installer gave you a warning that the file wasn't touched. In this case, you need to fix the file yourself, before the installation can finish successfully.
Another problem can be a syntax error in your scenery.cfg, which will have the same effect. Again, this is not an installer error, but a result of the file being already wrong before running it. And yes, FSX usually tolerates files with errors inside, it will just skip that section, that's why you might have not noticed it before.
If you either send me via email, or post here ( It's best to make a .zip of those files and send them via email), the affected files, I can check where the pre-existing error was.
The files are
%APPADATA%\Microsoft\FSX\EXE.XML
%APPADATA%\Microsoft\FSX\DLL.XML
%ALLUSERSPROFILE%\Microsoft\FSX\Scenery.cfg