Install and run on MacOSX


If you have trouble running VASSAL on MacOSX (11.7 and possibly later) - I.e., you can install by downloading the DMG from the site, but when you try to run it, then MacOSX complains that it won’t run the app because it was downloaded via Chrome/FireFox/… - do not despair - here’s how to get around it.

  • Open up a Terminal (Finder->Applications->Utilities->Terminal)

  • Change directory to your Desktop

     cd Desktop 
  • Run the following command

    curl -LO 

    and wait for it to finish.

    • curl is a simple web-client
    • -L means follow redirects, -O means uses given URL filename for output filename.
    • You may want to change the version number to what ever version you’d like.
  • Double click the VASSAL DMG now

  • Drag the VASSAL app to the installation directory as instructed.

If this is well-known and -understood and I’ve just overlooked it somewhere - my apologies. Anyway, I hope it will be of help.


An inability to open/mount a disk image because it was downloaded by Chrome/Firefox is a new one to me–I’ve been using VASSAL successfully on MacOS since at least that OS version and likely much longer. Gatekeeper blocking the actual app from running because it’s not signed is a well-known issue, but first time hearing of this one! Note that the command line won’t be of any help to Apple Silicon users who might run into this–they’d have to modify the URL to get the right build for that architecture.

Is there a way to get around the issue of it blocking the app from running because it’s not signed?

Could we see some screenshots of the problem? It would help to have more context around this. (I take it that this is a different issue from the one @JoelCFC25 points to in the wiki?)

Sure–see the troubleshooting note about this.


I didn’t mean to say you couldn’t “mount” the DMG- if you got that impression, then I wasn’t clear enough. What I meant to say is that you cannot run the app after it was installed.

The trouble is indeed as explained on the wiki

Well, the command line will help as long as you specify the right image to get. The list of images can be seen at GitHub - the user simply need to

  • right click the appropriate target, select Copy link address (or other OS-specific equivalent)

  • Open a terminal

  • Write

     curl -LO <paste copied link>

    and press enter to download

  • Then double click the downloaded file and install per instructions.

The appropriate link for MacOSX on Apple M1 and current release would be

For MacOSX on x8664 and β-2 of 3.7.0 would be

and so on.

The work-around on the wiki is indeed valid, but the curl trick is another way to get around the gate-keeper (sort of shows that MacOSX isn’t really all that secure as its made out to be).

So it seems the problem is known and there’s a fix (now two :slight_smile: ) so - as I said - my apologies.


That’s pretty amusing–and good to know–that downloading with curl evades Gatekeeper. Still, if you look at the sweep of history and the kinds of installation difficulties and troubleshooting questions users tend to post, I don’t have much confidence that there will be more than a handful of users savvy enough to use this method. I might, though! You should add your method to that wiki page.

My point about the command line example given was not that the technique wouldn’t work for other builds as long as you modified the URL target (as you later expanded on)–just that the specific one in the OP would not work for Mac users who don’t have Intel architecture.

I finally got around to add the method to the Wiki. Pending approval.