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$FG_HOME is a placeholder variable representing the path to where user-specific FlightGear data is stored (not application data). Unlike $FG_ROOT, $FG_HOME is not an environment variable that needs to be configured for FlightGear to work. $FG_HOME is the only place were FlightGear data is written to as $FG_ROOT is generally read-only.

$FG_HOME is only used to refer to the operating system specific location for some settings/folders. The actual location of $FG_HOME is determined by the fgfs binary during startup and is a directory that varies with the operating system supported by FG (Windows, OS X and Linux).

Note$FG_HOME and the /sim/fg-home property should be considered read-only, because they cannot be affected during startup or at runtime.
Note  The Fgfsrc config file will not actually be saved in $FG_HOME, but just in $HOME


In $FG_HOME is information stored between sessions. That information is foe example configuration/preferences, properties marked with the user-archive attribute and aircraft-specific settings (using the data helper class in aircraft.nas). $FG_HOME is also the location for the SQLite-based NavDB cache.

Common paths

You can determine the location of your $FG_HOME by using the property browser and checking the value of /sim/fg-home, but the usual paths are shown below.

The /sim/ property subtree is also the place where you can find other folders, such as fg-root, fg-scenery and the current working directory (fg-current).



Mac OS X

~/Library/Application Support/FlightGear (to learn more about viewing hidden folders, see [1])

As all future FlightGear versions will take their preferences from here, it is a good idea to have their access available easily.

Desktop/Finder/Go/Go to Folder is where you need to start.

When given the option, input: ~/Library/Application Support/FlightGear

It is probably a good idea to have ~/Library/Application Support/FlightGear saved on a Stickies note just in case you forget it.

If you want/need to refer to any of these files frequently, you could make an alias of a file, or the whole folder, and place it somewhere easier to access. TerraSync data is also stored inside the user's home folder, as it is the only location we are permitted to write too, $HOME/Library/Application Support/FlightGear, which technically is the value of $FG_HOME.

The OS X launcher doesn't actually set this path (any more), this location is the default used by FlightGear itself. You can of course override these paths and set $FG_HOME or the TerraSync path manually, from the command line or a configuration file, but the default paths should do what you need.


FlightGear 3.0 and later


%HOME% is usually C:/Users/User name

Before FlightGear 3.0


%APPDATA% is another environment variable that depends on your Windows version. On XP and older, it can be found under C:\Documents and Settings\User name\Application Data. On Vista and later it can be found under C:\Users\User name\AppData\Roaming. The folder is hidden by default. See these instructions to show the folder.

Use in troubleshooting

As one user once said, "When in doubt delete $FG_HOME". Many problems, including corrupted databases, broken TerraSync and many others can be fixed by deleting fgfs_0.txt, fgfs.txt, terrasync_cache, and the Navaids database.

When you encounter problems, try deleting the files, but always keep the fgfs.log and fgfs_0.log log files to help in troubleshooting.

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