If you've been experiencing difficulties launching Final Fantasy IX on Steam after installing and uninstalling the Moguri Mod, you may need to make some adjustments in the Windows Registry. Follow these steps to resolve the issue

Step 1: Open the Windows Registry Editor. To do this, follow these steps:

Press the Windows key on your keyboard or click on the Start menu icon. Type "Regedit" in the search bar and press Enter. This will open the Registry Editor.

Step 2: Navigate to the correct location in the Registry. Follow the following path: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options

Step 3: Once you're in the "Image File Execution Options" folder, look for a folder named "FF9_Launcher.exe"

Step 4: Right-click on the "FF9_Launcher.exe" folder and select "Delete" to completely remove this folder.

Step 5: Restart your computer to ensure that the changes in the Registry take effect.

After completing these steps, the issue of launching Final Fantasy IX should be resolved, allowing you to install and play the game as usual.

Important Note:
This problem is largely due to the "SteamFix" configuration. By deleting the
"FF9_Launcher.exe" folder from the Registry, you are undoing this configuration so the game can run properly.