How do I convert a SMP server world into a Single-player compatable world?

Question

I had a Minecraft world on Minefold. I archived my Minecraft world just before Minefold closed about a year ago.

I'm trying now to open the world in my local Minecraft installation on OS X, but it doesn't show up in the worlds list.

To import it, I simply unzipped the archive from Minefold into my ~/Library/Application Support/minecraft/saves folder.

I'm running Minecraft 1.8, and I don't have any mods installed.

There's no error; the world just doesn't show up in my list of worlds after I click [Singleplayer] (or [Multiplayer]).

Now, the big clue is that the directory structures are different between my locally-created worlds and the world created on Minefold, but I can't figure out how to adapt the files to make them match:

This is a screenshot of my saves folder. I've circled in blue "local" and "minefold", which contain data files for the local and Minefold worlds, respectively.

I bracketed similar filenames in both worlds, but I'm flummoxed in that the Minefold version has three (3) sets of data files, whereas the local world has only one (1) set of files (even though I have visited Nether in the local world).

How do I load my old Minefold world locally?

Answer 1

There is a simple way to combine your Multiplayer world for Single-player use.

Notice how your single-player worlds are saved in region, DIM1 and DIM-1 folders. Each of these folders is your dimension.
Multiplayer servers saves each dimension in its own folder, while the game (single-player) saves it as a whole folder of its own.

So, what you want to do is copy the DIM1 (The End) and DIM-1 (Nether) into the folder with the overworld dimension in it (level folder; as it is called in your screenshot), and then you can put your level world folder straight into your saves folder, in the Users/[Username]/Library/Application Support/minecraft/ folder, which then will run perfectly fine with all your dimensions intact.

Player inventories, locations etc. are stored in the overworld folder (level), so all locations will be preserved. (Means if you were in the nether, you'll log back on into the nether, or where the level.dat says you are)

You should end up with a file directory like such:

...
    - local
         - ...
    - minefold
         - ...
         - level
             - data
                  - ...
             - DIM1
                  - ...
             - DIM-1
                  - ...
             - players
                  - ... 
             - region
                  - ... 
             - uid.dat
             - level.dat
             - level.dat_old
             - session.lock

Note: "..." means things not included/not important.

---

The DIM-1 folder contains data for your Nether,
The DIM1 folder contains data for The End and,
The region folder contains data for your overworld.

Everything else, you do not need to touch.

Answer 2

There is also a mod you can load using forge called world downloader, using it you can download most servers as far as your char can see