This article covers the following platforms
MSFS 2024
MSFS 2020
ATS
FSX
Prepar3D
The Virtual File System (VFS) is how Microsoft Flight Simulator (MSFS) organizes everything the game needs — aircraft, sceneries, avionics, and much more. It helps the game find and use these files.
How the VFS is structured
The VFS acts like a set of layers: Core packages, Official packages, and Community packages. It makes all the files look like they’re in one place, even when they’re not. When there are multiple versions of a file, the game uses the latest one loaded, typically the one in the Community folder — the folder where MSFS loads add-ons from.
How add-ons use the VFS
Add-ons are files users install to enhance or modify the game — anything from new aircraft to altered menu systems like Flow. When you install an add-on in your Community folder or through the in-sim Marketplace, its files are added to the VFS so the game can find and load them.
How conflicts happen
Conflicts can arise when two add-ons modify the same game element — a font file, avionics, visual effects, textures, and so on. If files with the same name come from different add-ons or core packages, the game only uses the file from the add-on that loads last, typically one in the Community folder.
For example, if multiple add-ons change the same font file, avionics, tail registrations, or other interface elements may not display correctly.
Add-ons load alphabetically. In a conflict, the package whose name comes later in the alphabet overrides the other. Managing these conflicts takes careful organization of add-ons and, sometimes, a management tool like Simstaller.
Core file replacement
Some add-ons change important game files. This may be required for the add-on to work, but it can cause unexpected behavior because some of these files are used in many parts of the game. For example, if an add-on changes an instrument file for one plane, it might accidentally change the instruments for some or all planes in the game, not just the one the add-on targets.
Manage add-on conflicts
The key is understanding what each mod changes and organizing your mods so they don’t overlap unless they’re designed to be compatible. Tools like Simstaller let you navigate the VFS and find conflicts.