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Installing VASSAL

I'm not sure what package to download.

You should download the package that matches the architecture and OS of your system.

  • For Windows, instructions for checking if you have a 32- or 64-bit processor and whether it is x86 or ARM are here.
  • For MacOS, instructions for checking if you have an Intel or ARM processor are here.

I'd like to play VASL but i can't download the Vassal engine.

Technical help for individual modules is beyond the scope of this FAQ.

Post a message onto the Forums and detail the exact problem/error messages you are getting. You can get detailed technical help there. There are also web pages and discussion groups dedicated to specific modules. Check the Module page and the Module Talk page on the website for more details.

VASSAL does not start.

Follow the troubleshooting steps here.

Downloading Modules

I tried to download a module, but I got a Windows Media or MPEG file instead

Any module I download off this site that is a .mod (or sometimes .zip) shows up in my folder after download as an MPEG. When I try to load these modules by double-clicking them, Windows Media Player starts and I get an error message telling me why it won't run on Media Player.

Just rename the .mod files to .vmod and double-clicking should work (Vassal 3.1 and later).

The Zip files 'should' contain a .mod or .vmod inside them, if so, rename it to .vmod. If not, then just rename the .zip file to .vmod.

You can open any module, regardless of name by first starting up the Vassal Module Manager (Click on the Vassal shortcut instead of double clicking on the module). Then File -> Open Module and navigate the the module file.

The .mod extension is used by Windows Media Player to identify movie files. Vassal modules have historically also used that extension. Because of this conflict, new modules should use a .vmod extension. But some of the older files have not been updated yet. They really are Vassal modules, but the computer gets confused because another program uses the same extension to mean something different.

The module I downloaded expanded into a bunch of files

Sometimes your web browser will automatically expand module files, since they are really just zip archives. You can tell this happened if there are a bunch of files and folders, including among others, an "image" folder. This seems to be more common on Macintosh systems.

What you need to do is prevent your browser from doing this automatic expansion. The way to go about this depends on the browser that you use:

  • Firefox
    • Right click (Mac: control-click) on the link and choose "Save Link As ..." from the popup menu.
  • Safari (Macintosh) either
    • Right click (control-click) on the link and choose "Download Linked File" from the popup menu.
    • or edit the Safari "General" preferences and make sure 'open "safe" files' is not checked.

Using VASSAL to play existing modules

I am getting an Exception Error, what do I do?

If vassal crashes, it creates an Errorlog file and an automatic bug report form, which you can fill out and send to the Vassal team. We take all bugs seriously so it is important that you send in those forms to help us improve Vassal.

How do I do a right-Click on a Macintosh computer?

If you are using a single-button mouse, you can use control-click to simulate right-click. This is a standard MacOS feature.

How does 'Choosing Sides' work?

When a module is created, the author has the option of defining Sides (e.g. German/Russian, Red/White). Not all modules have sides defined.

When you create a new game, or load a scenario file that does not have all sides allocated, you are presented with a pop-up menu of the sides to choose from. When you select to play a side, the current password you have defined in your preferences is associated with that side in that game and is saved (safely encrypted) in the save file. When you next load that save file (or a later save file produced by your opponent), your password is matched with the passwords associated with the sides in the save file, and if there is a match, you are automatically allocated to play that side without seeing the pop-up dialog.

When playing a game with sides, you have the additional option to Resign from the game. Resigning disassociates your password from the side, allowing the next player to load the save file (or syncronize if playing on-line) to choose to play that side.

IMPORTANT If you change your password in the preferences, it will no longer match the password for your side in the game and you will no longer be able to access your peices!

How do I create a Scenario start file with both sides not owned?

Choose a side, set up the counters, then hit the 'Retire' button before saving the scenario file. Then load that same scenario file and select the other side, set those counters up, click 'Retire' and save the final save game. No need to use different machines or passwords when doing this.

I can no longer access my Masked or Invisible pieces?

Have you changed your password in preferences?

The ownership of Masked pieces and Hidden pieces (and of Concealed counters in VASL or VSQL) is based on your password when the pieces are masked or hidden. If you subsequently change your password, you will lose ownership of those pieces and you wills see them as your opponent sees them.

The solution is to change your password back to what it was.

I've forgotten my password. How can I get it back?

Unfortunately you are out of luck. The passwords used in Vassal are secure and there is no way to recover them. You will have to try to figure out what you chose as your password.

Why can't I see all the events and pieces when the other player moves?

This is usually caused by not being synchronized with the other player. When you start an on-line (server) game, all players must be synchronized.

One of you has to right click on the other's name in the server controls and select synchronize. With multiple players everyone should pick a single player to synchronize with, such as the player who initiated the game. This will make sure that everyone’s game position is consistent.

When you synchronize, any side selection, piece movement and map selections you have performed will be reset and replaced with the game information of the player to whom you synchronized. [User Guide]

The map doesn't appear when I close and reopen a game?

When opening a new game, the Chat Window is sometimes maximized and the Map Window minimized so you do not see the map at all. There are a couple of ways to fix this:

  • Open and close a Game Palette.
  • Move your cursor to the bottom of the screen until the double headed arrow appears, find the divider bar and drag it up.
  • Start a fresh VASSAL session.

The map sometime flashes onscreen & then disappears. Other times it never appears at all.

This is a symptom of too little memory being allocated to the VASSAL program.

Vassal 3.1 and later allow you to set the memory for a module using the preferences for that module. Open the preferences and increase the maximum amount of memory. This value should generally be lower than the maximum amount of RAM your system has installed.

For earlier versions: When using Web Start to launch VASSAL, it is allocated 256MB. When running the manual installer, you can select the amount of memory to allocate to VASSAL during installation.

How do I make a window appear on a second display?

My computer has more than one display. How can I put a window on the second display?

  • Open the preferences panel for the module.
  • Uncheck the option "Use combined application window".
  • Close the module.
  • Open the module again. Each panel will be in its own window, which you can place as you like.

Why are the dice rolls not random?

Actually, the dice roller in Vassal produces great random numbers. Players often suspect that there is something wrong with the die roller after observing a run of the same number. This turns out to be a common reasoning fallacy when observing random number generators. It just seems wrong for there to be that many consecutive numbers that are the same. But the opposite is really true. If sequences of the same number did not appear, then the randomness of the die rolls would be suspect.

Rest assured that the programming team has carefully tested the die roller code and it passes the ent statistical tests for random number generation. If you want to learn more about this, see here or the Wikipedia article

Obsolete Questions

Linux Installation tips

Warning Warning: This entry is obsolete.

I have a debian/sarge install which should be very similar to ubuntu, and I was able to install the Blackdown j2re1.4 package which has javaws.

Add this line to /etc/apt/sources.list

deb sarge non-free

(All 1 line)

Then: $ su - root

  1. apt-get update
  2. apt-get install j2re1.4
  3. exit

See: Here's a screenshot.

Now you should have Java Web Start 1.4 link in the Applications/Internet menu. When you run this, you should be able to paste the .jnlp download link from the vasl download page. EG:

This is the easiest way to run vassal/vasl

There will be an option to install a desktop shortcut. This puts it in an old gnome desktop location, but the shortcut is good. What I do is move this over to a more sane location.

Eg: $ mkdir Desktop/Shortcuts $ mv ".gnome-desktop/VASL 5.0.desktop" Desktop/Shortcuts

Then you can open up the gnome file browser (nautilus) and type this in the Location bar:


Open up the Shortcuts folder on the desktop, and you can drag the VASL5 shortcut to the Games menu, and now VASL5 will be in the games submenu of the gnome menu.

See: Here's a screenshot.

Now you can run VASL from the games menu. This is pretty convenient.

See: Here's a screenshot of a game in action.

VASSAL is not automatically updating to the latest version. What's wrong?

Warning Warning: This entry is obsolete.

This will only happen if the shortcut is not ending like this

....................................Application Data\Sun\Java\Deployment\cache\javaws\http\\P80\DMws\AMvassal.jnlp

Right click on your desktop shortcut and select properties.

Possible reasons :-

1. Its a shortcut to the downloaded stand alone version which will always be fixed to the initial version downloaded i.e you selected download installer for windows.

Note this isn't needed if you can successfully launch online as you can use the Java application console "C:\Program Files\Java\jre1.5.0_01\bin\javaws.exe" to launch Vassal Offline.

2. You are Launching a shortcut to a specific module which uses an older version of Vassal. When the module is developed /created it is associated with the version the developer is using (i.e when you use edit module and save it)

This is always true of commercial applications like Lock'n'Load and Corsair Leader.


1. Load your Java console Javaws.exe right click on Vassal and select uninstall shortcuts.

2. Then right click on it again and select install shortcuts.

If that doesnt work :-

1. Load your Java console Javaws.exe select vassal and remove application (bottom Right) 
2. Go to Vassal Welcome screen and click on "click here to Launch Vassal" 
3. If its not still loaded from above then Load Java console, right click on Vassal and select install shortcuts. 

VASSAL tried to update to a new version, but gave me an error

Warning Warning: This entry is obsolete.

Found unsigned entry in resource: (


Unable to load resource: (, x.y)

Try clearing the temporary files in WebStart:

Assuming you are running windows XP, doubleclick on the "java" icon in your control panel (i.e. "start/control panel"). This should start up the Java Control Panel. You should see a block near the bottom that says "Temporary Internet Files." Click on the "Delete Files" button. There are three checkboxes you may select. The only one I needed to select was the middle one: Downloaded Applications. Make sure that one is selected. Click Ok.

You can also run the manual installer