If anything goes wrong and you didn’t pay for it, please do some homework since most of the freeware developers double check their files with beta testers before publishing.

Here are a few tips:
The (new scenery) folder goes into Custom Scenery, not the .zip. In other words, the compressed file needs to be uncompressed before joining other precious sceneries in Custom Sceneries. Some developers, -but very few since we are smart-, use Russian doll folders, a folder containing a folder with the same name.

It won’t work.
Custom Scenery expects a folder containing, Earth Nav Dat, earth.wed.xml, objects, plugins ....

I always check downloads' contents before placing them in the proper section, it's the best way to avoid unnecessary aggravations.

Make sure you don't have two instances of the same airport running at the same time. They might merge, but often, the sim will crash. Be aware of that kind of issue if you use scenery packages, you might not be able to find out about double sceneries if you don't know the exact contents of these.

Developers use certain libraries, if you don't have these libraries, it won't work. Developers specify the version they used to build the airport. Most of the time, it's XP10, if you don't have XP10, it won't work. Some developers use third-party libraries in addition to OpenScenery II, make sure you have these in Custom Scenery (Ruscenery, ff library, R2_library).

Developers usually announce their third-party libraries if any in their requirements. It's a good habit to have them all anyway. Make sure yours are up to date. Most common third party libs are:
- RuScenery (1),
- RU2,
- FF,
- OpenScenery II.

You shouldn't have to download Autogate, Flags of the World, Mow my X-Plane,... unless you are a developer. Always read the requirements before using a new scenery.

If something still goes wrong, check the log.text in your XP10 folder. Trash that folder when you can, it needs fresh data. It will be restored each time you fly. Before the log.text announces a crash, usually at the end of the file, it gives you precious information about what is missing and causes the sim to crash.

Can't find forest/beach ... announces a missing file. Make sure you have the latest version of OpenScenery II in your custom scenery. Of course, you will need to get that missing file, it's either in a library you didn't download or the developer forgot it. It may occur in rare circumstances (bad link in WED's hierarchy pan).

Some errors are not significant, they are usually not announced by an error message, they might just be some bug in the system, not sure: 0:00:00.000 I/SCN: Failed to find resource 'test/AGtrees_test.for' (parent = 'Resources/default scenery/airport scenery/Common_Elements/Misc_Buildings/...

Please read the log.text carefully since another airport in the vicinity could be the reason for a crash. Reading a log.text is using common sense, even I can do it.

P.S.: Some developers will use a Placeholder Library in order to avoid crashes among those who don't have OpenScenery.