How to avoid overwriting or duplicating .json files when installing new MSFS add-ons

Ron,

In MSFS it helps to separate two different things:

1) Add-on “.json” files inside each package
Those are part of the add-on itself (usually in that add-on’s own folder). If you drop a new add-on into Community, it shouldn’t be “overwriting” another add-on’s JSON unless you’re literally copying files into the same add-on folder, or installing two versions of the same add-on with the same folder name.

2) MSFS “cache/index” type .json files
The sim can create/update some JSON files on its own (scenery indexes, caches, etc.). You generally don’t manually merge those—MSFS will rebuild them as needed.

What typically causes duplicates/overwrites

• Installing an update “on top of” the previous version but not deleting the old folder first, leaving two similar folders behind (e.g. myairport and myairport_v2).
• Unzipping an add-on and accidentally nesting folders (very common): Community\SomeAddon\SomeAddon\.... The sim then reads it weirdly or you end up trying to “fix” it by copying individual files around (which is where overwrites happen).
• Two add-ons using the same package folder name (rare, but it happens with sloppy repacks).
• Using a third-party installer that drops files into an existing folder instead of replacing it cleanly.

Safe install routine (avoids almost all of this)

1. In Community, if you’re installing an update to something you already have, delete the old version’s folder first (or move it somewhere as a backup).
2. Unzip the new add-on to a temporary location (Desktop, Downloads, etc.).
3. Check the folder structure before you copy it in:
   • You want: Community\PackageFolder\manifest.json and Community\PackageFolder\layout.json (those two are “normal” for MSFS packages).
   • If you see: Community\PackageFolder\PackageFolder\manifest.json then you’ve got one extra folder layer—copy the inner folder instead.
4. Copy the entire package folder into Community. Don’t drag individual JSON files around.
5. Keep only one version of that same add-on active at a time (don’t leave an old folder in there “just in case”).

If you mean the sim keeps regenerating JSON files…
If you’re referring to JSON files that appear outside the add-on’s own folder (or reappear after deletion), tell me where you’re seeing them and what they’re named—those may be normal MSFS-generated files, and “fighting” them can cause more headaches than it solves.

A couple quick questions so I don’t guess wrong

• Which JSON files specifically are you talking about (file names), and in what folder path are they located?
• Are you installing updates for the same add-on, or completely different add-ons?
• Are you using any add-on manager/installer, or doing manual unzip/copy into Community?