JMRI Setup: Configuration Files
This section attempts to explain where JMRI Configuration
(settings) Files are stored on your computer and what
information they contain.
- Configuration File Locations
There are two places where JMRI Configuration Files can
- The originally-distributed versions of JMRI
Configuration Files live in an 'xml' directory in the
JMRI application package and its subdirectories.
(The exact location depends on how you
installed JMRI on your computer)
that anything you modify here will be lost when you
update JMRI to a new version.
This is not the right place to make changes!
- The user's JMRI Preferences directory and its
subdirectories is also of importance. JMRI looks here
first for any files it needs.
You should put any locally-modified versions of files
here so they don't get overwritten by a JMRI update.
Any files that the program writes to containing local
information, e.g. Roster entries and Panel files, are
also written here.
The default user's Preferences location varies by
computer operating system. Normally, it's located:
The easiest way to find the preferences location is to
start a JMRI program, e.g. DecoderPro or PanelPro, select
"Locations..." from the "Help" menu and click on [User Files
- On a Linux machine, look for a
directory in your home directory.
- On macOS, Preferences are stored in a "JMRI"
folder in the /Users/me/Library/Preferences/
- On Windows, this can be in a number of places
depending on the Windows version you're running and
whether you have multiple users configured. Start
by looking under "Documents" or "User Documents" or
"Users and Documents". You're looking for a folder
A special treat for Windows users: if you go to the Windows
Start Menu, in the JMRI section, you can select
"Preferences" to have it open that directory for
- User files can be stored under the preferences location,
but JMRI can also be configured to put them somewhere else.
You may set or change the location scripts and
user files in the
Preferences... -> File Locations panel. Note
that changing the "User Files Location" will also
change the default location for Panels, Rosters
- Types of Configuration Files
Inside your JMRI Preferences folder are a number of types
of configuration files used by DecoderPro:
- Decoder definitions - Stored in the
decoders subdirectory, one for any
customized decoder; these define how a specific family
of decoders is configured.
- Locomotive configurations - Stored in the
roster subdirectory, one for each
Locomotive; these record the specific configuration of
each Locomotive in your Roster.
- Programmer definitions - Stored in the
programmers subdirectory when you've
used at least one Programmer; these define the formats
for the various programming sheets that are available
- The DecoderPro folder, containing your
- General Configuration Files
There are many more JMRI Configuration Files, some shared
by applications, which live in the user's Preferences
- roster.xml - an index of your
- decoderIndex.xml - an index of the
available decoder definition files. It also contains
the information on which specific decoder model uses
which file, how to identify them, and what options they
- names.xml - not used during normal
operation, this is a list of the standard Variable
Names for use in programmer definitions.