Minecraft puts the data in %AppData% , so you can just make batch files which set %AppData% to some other location before running the game.
This is a trivial but flexible working example:
@echo offset LAUNCHER=
c:\games\minecraft\minecraft.exeset SUPPLEMENT=.minecraft-supplementalset APPDATA=%APPDATA%\%SUPPLEMENT%%LAUNCHER%
This will make that launch of Minecraft keep and look for its data (including your saves and even mods) in %AppData%\.minecraft-supplemental\.minecraft\ .
(The extra level of folder structure is unnecessary but harmless, and it would be hard to eliminate it without breaking the sorts of things that the %AppData% convention was designed to avoid breaking.)
Note that this will keep everything separate -- remembered login, achievements, saves, Minecraft version, mods -- everything.
As a bonus, this not only means that you can keep different versions of Minecraft installed, you can segregate different login names into their own installs with their own saves, useful for sharing a computer with other Minecraft players.
You can make multiple versions of that batch file and change the %SUPPLEMENT% variable to keep the copies' data separate.
(Yes, it's currently set to a dumb name.
Customize it to taste.
I suggest .minecraft-[username] .)
You can even use different Minecraft launchers by changing the %LAUNCHER% variable, allowing different versions (or users) to use different launchers.
gaming.stackexchange.com/users/12219/Trejkaz
Might I suggest Sandboxie ?
Its original intentions were more along the lines of security, however, it should serve the purpose you are looking for.
Any program run in sandboxie is forced to keep it's files separate of everything else in your system.
As long as you run one version or another within Sandboxie always, you should be fine.
gaming.stackexchange.com/users/1393/Aeo
I found this:
The Minecraft Version Changer Tool .
It includes a jar downloader that can download about 20 versions from early Alpha to Release 1.1 (including many snapshots).
I expect 1.2 to be added soon, as they seem to do a very good job keeping it updated.
I have tested it, and it works well for me.
It completely isolates the different jars
so I am able to keep one .jar for modding without it affecting my other one at all.
gaming.stackexchange.com/users/5029/John the Green
The Magic Launcher lets you do this.
You could use the Technic Launcher .
It's Open Source, so you can modify the source code to use the versions you desire.
gaming.stackexchange.com/users/88/Zommuter
You could install each one on different Windows users, since the AppData folder is in the user directory, and not the program files directory.
gaming.stackexchange.com/users/13359/Brad
Ever since 1.6.1 (July 2013), the Minecraft Launcher has supported multiple Minecraft versions installed concurrently through the use of profiles.
To create a separate version, begin by pressing the New Profile button in the launcher: Next, change the version number from 'Use latest version' to the version you want: If you want to use a snapshot version or an old Alpha/
Beta build, you will need to click the checkbox to enable them.
Optional step: if you want to keep the installation separate from your main Minecraft installation (e.g. you are playing a snapshot which could corrupt your worlds if you play them accidentally in the wrong version), tick the 'Game directory' box and choose the folder of your choice: Finally, click save profile, switch to it in the dropdown menu, and click Play to download the specified version and play it!
gaming.stackexchange.com/users/104515/angussidney
In Windows 7 you can make two different Minecraft folders wherever you want, then put a directory symbolic link (that points to one of those folders) named .minecraft to %APPDATA% MKLINK /D
%APPDATA%\.minecraft path\to\your\directory
To change the version, remove the link and make a link to the other folder.
Linux, KDE:
In Dolphin file manager drag one of your folders to your home folder, select "Make a link" and rename it to .minecraft (note that it will be hidden, so you have to press Alt
+ . to show it and remove.
gaming.stackexchange.com/users/2267/BlaXpirit
Quite a few people use a launcher called MultiMC .
This allows you to set up multiple installations of Minecraft and swap between them.
gaming.stackexchange.com/users/8581/James
This isn't a perfect solution, but you could always install linux to a flash drive (I'd suggest an 8 GB or larger card, and installing Ubuntu) and boot/run a second copy of minecraft from it.
As a bonus, you would now have a portable copy of minecraft.
gaming.stackexchange.com/users/7992/Fambida
You could go into the "bin" folder of ".minecraft" and then copy and paste your minecraft.jar file in another folder, keeping it there until it's needed.
You can locate your bin folder by pressing your start menu, type in "%
appdata%"
-> "Roaming" ->
".minecraft
" -> "bin", click on "bin" and back-up your "minecraft.jar" file at the bottom.
When you want to play a previous version of Minecraft, just simply delete the "minecraft.jar" that's already in your "bin" folder, then copy and paste the back-up "minecraft.jar" into the "bin" folder and you're set.
gaming.stackexchange.com/users/30392/zCynic
When a major version of Minecraft is released, it takes a while before mods are updated to work with it. It can happen that you want to install the new version, but keep a copy of the old version with mods installed.  Windows version keeps data in  %appdata%/.minecraft  regardless of the executable's version. Is it possible to keep two versions of Minecraft installed at the same time, without conflicts?
How do I keep two different versions of Minecraft installed?
gaming.stackexchange.com
<minecraft-java-edition>
gaming.stackexchange.com/questions/29272
gaming.stackexchange.com/users/3454/Joe Dovahkiin
There are various tools that let you do this: Minecraft Version Changer Tool, Magic Launcher, and Minecraft Launcher. You can also install each one on different Windows users or go into the bin folder of minecraft and copy and paste the minecraft.jar file into another folder. The most prominent solution is using Minecraft Launchers, although creating different executive and save files works as a legitimate option. Running the game on a different OS is also advisable.
Creating alternative save and executive files could solve the problem. Two version can be installed at the same time using specific Minecraft launchers. Installing a game on a flash drive could be a solution.