I have all libraries (EZ, RWY12, Sidney_Schwartz_lights, CeyX_Sceneries_Libraries) in one folder (FSX\Addon Scenery\EZ_RWY12 Library) and there isn't any problem.
Dieter
Same with me Dieter but it was that #2$%^@@ 'cursor bounce' that misplaced the .bgl files from Xavier's library and of course the sim could not find them. Finally discovered the misplaced files and all better now.
As a matter of fact I use a scenery library that I had in FS9 that started from a 210MB download from the old Texas International Airline VA site By Robert Degegorio (sic). Unfortunately it is now defunct I guess because the site is no longer on the web. I have been adding to this library every time I get new library objects so it is quite extensive. EZ, RWY12, Abacus, Nova, CeyX, and 45 other downloads from the usual places.
Of course this does lead to some overlap when addon scenery includes some of the same objects within the download but that is life as they say. I try to eliminate the overlap as much as possible by combining the libraries and only adding a file that exist if it is newer than what I already have.