Sharing of achievements across Windows users

The game saves the state of universe and characters directly in the game folder instead of the user folder. If you wish to have progress seperated you need to make 2 different starbound installs.
If they share the same steam account then steam achievements will still be unlocked for both.

 

As mentioned above you'll need 2 different Starbound installs in this case, as in 2 totally different locations to where the game is installed because Starbound stores the saved data directly in the game folder. If both installs share the same folder then they share the same universe as well as any achievement triggers that are universe dependent. That the universe is shared between characters is intended.

For example:
Windows user A installs to "C:\Program Files\steam\steamapps\common\starbound" as well as Windows user B -> both have the same universe and character files shared regardless of steamaccount and/or windows user account and steam achievements are tracked on the universe and not account.
If the locations differ between the two users then both users have different files and their achievements tracked individually which is what you're looking for. Another solution to this would be working with a second config file and launcher arguments within steam if you want to stick with 1 install which requires editing some stuff.

 

As I said, it's intended that the universe is shared between different characters.

If you're stuck with one library only then you'll need to setup an additional config file and add an argument to the steam launch options for Starbound.
Steps for the additional config are:
1) Go to the location where Starbound is installed, you'll find a folder called win64 in there.
2) Inside the win64 folder there will be a file called sbinit.config.
3) Copy the file and rename it to something else, e.g. sbinit_second.config (any name is fine, just keep the .config extension)
4) Open the newly copied file with a text editor of your choice. The contents should be something like this:

Code:

{
  "assetDirectories" : [
    "..\\assets\\",
    "..\\mods\\"
  ],

  "storageDirectory" : "..\\storage\\",

  "defaultConfiguration" : {
    "gameServerBind" : "*",
    "queryServerBind" : "*",
    "rconServerBind" : "*"
  }
}

5) change the names of "mods" and "storage" to something else and save it, e.g.

Code:

{
  "assetDirectories" : [
    "..\\assets\\",
    "..\\mods_second\\"
  ],

  "storageDirectory" : "..\\storage_second\\",

  "defaultConfiguration" : {
    "gameServerBind" : "*",
    "queryServerBind" : "*",
    "rconServerBind" : "*"
  }
}

6) Open steam and select Starbound in the library of the account which you want to have a different save location for.
7) Right click and select Properties.
8) In the general tab of the properties find the line for "Launch Options".
9) Put the following to the options:

Code:

-bootconfig sbinit_second.config

The filename given in the argument MUST be the same as the one you copied.

It is very important that you do not break the file structure of the config file, otherwise the game will not launch! Also on the account where you're changing the data it will be an empty universe again so anything build in the previous universe will be lost. Also character files need to be transfered manually unless it's okay to completely start over on this account.