The save folder is located in Documents\EA Games and its name is typically:

• The Sims 2
• The Sims 2™️ Ultimate Collection
• The Sims 2 Legacy

Some of us have more than one save folder (e.g. one for playing and another for testing).
Typically, to make a certain save folder used by the game, you need to rename it to match the original save folder name (mentioned above).
However, renaming folders can cause problems if you synchronize folders to another drive or to the cloud.
It also makes it harder to recognize which folder contains which save.

There's another way to switch between save folders – without changing their names. It's based on changes in the registry.
This tutorial will show you how to prepare files for switching save folders used by the game.

Making a backup of registry
Modifying the registry may cause serious problems if done incorrectly. Therefore, let's back up it first.

1. Select Start, type regedit.exe in the search box, and then press Enter. If you are prompted for an administrator password or for confirmation, type the password or provide confirmation.
2. In Registry Editor, select File > Export.
3. In the Export Registry File dialog box, select the location to which you want to save the backup copy, and then type a name for the backup file in the File name field, e.g. TS2 - backup registry
4. Select the Selected branch option at the bottom of the dialog box.
5. Put the appropriate path in the field below the selected option:
   
   • for Legacy Collection (the path contains Ultimate Collection, it's not a mistake):
     
     Code:

     HKEY_CURRENT_USER\Software\Electronic Arts\The Sims 2 Ultimate Collection 25

     
     
   • for other installations, such as Ultimate Collection:
     
     Code:

     HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\EA GAMES\The Sims 2

6. Select Save.
   If you get a The selected branch doesn't exist error, make sure you've inserted the correct path.
7. Close Registry Editor.

This section is based on a Windows' article.
Preparing a base file with original save folder name

1. Copy the backup file you've exported.
2. Rename the copied file to indicate that it's for the original folder path, e.g. TS2 - switch to main save
3. Open the copied file in a text editor, e.g. Notepad.
4. Remove all the lines except for three:
   
   • the line that starts with Windows Registry Editor,
     
   • the line with the registry path you've used to export the backup file,
     
   • the first line that starts with "DisplayName".
   It should look something like this:
   
   Code:

   Windows Registry Editor Version 5.00
   
   [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\EA GAMES\The Sims 2]
   "DisplayName"="The Sims 2"

5. Save the file (not as new).

Preparing a file for a different save folder

1. Copy the file you're prepared in the previous step.
2. Rename the copied file to indicate what save folder it is for, e.g. TS2 - switch to test save
3. Open the copied file in a text editor, such as Notepad.
4. In "DisplayName" line, after the = sign, put the name of the save folder you want to use in quotes (").
   For example, if the folder name is The Sims 2 TEST, the line should look like this:
   
   Code:

   "DisplayName"="The Sims 2 TEST"

5. Save the file (not as new).

Preventing Steam from overriding your settings
Steam replaces some registry entries every time you start the game.
But there's a way to prevent it from overriding your settings.

1. If you haven't already run the game after installing it, run it, wait for it to load, and then close it.
   Steam must create registry entries for the game to work.
2. Open the game installation folder.
   It's usually Program Files (x86)\Steam\steamapps\common\The Sims 2 Legacy Collection
3. Move the 3314070_install.vdf file from the installation folder to another location.
   For example, you can create a new folder _Backup in the installation folder and put the file there.
   If something goes wrong, you can restore the file to the installation folder.

Switching to a different game folder

1. Double click the file you've prepared for a certain save folder.
2. If you are prompted for an administrator password or for confirmation, type the password or provide confirmation.
3. In the Registry Editor dialog box, confirm that you want to continue adding information.

The game should now use the selected save folder.



Other notes
If the folder name you put in the registry doesn't exist, the game will create it – just as if you were running the game for the first time.

Restoring the registry backup
If something has gone wrong, follow the steps in the switching to a different game folder section but use the backup file instead.

Credits
Blueybre
ivycopur – figured out how to make it work in the Steam version of Legacy Collection

Thank you @Nopke Very useful, I do similar for my gamedata (installation files) as I often want to test things with no overrides, or with a specific lighting mod, or with clean templates and so on. I never thought to do it for the userdata, I just have scripts to swap them in and out and rename them. Great that you figured out how to make it work in all gameversions! Thank you @Blueybre and @ivycopur too.

Oh! i need to do this, to switch the registry entries between Legacy and UC. Because I can only have one of them running at a time, and uninstalling/reinstalling is tedious. Is HKEY LOCAL MACHINE the only registry entry I need to change to switch games?

@rhiamom What do you mean? As far as I know, you can have both games installed at the same time and they're both usable. They will just use different save folders.

When the new release was brand new I tried having both, several times, but only the last installed one would run. So I assumed conflicting registry entries. But I just tried it, and it is working perfectly. Two Sims games, 2 versions of SimPE, all working.

Thanks so much!

I've completed this with two bat files to launch normal/testing game after the switch



I wonder if I can get rid of the pause but still have it wait for the registry edit before starting the game