As of today I have installed the remaining scerery off all scenery using the all selection button of the scenery installer program . Firing up Xplane11 in the Washington area, more precise airport S52, I get a "Missing scenery" error" and a possibility to install the missing scenery. When I push that button the installer starts and when it has checked my installed scenery files, no more scenery is left to download (0 MB). When I start Xplane11 again in that region the "Missing scenery" error still occurs.