If you installed Minecraft: Java Edition on a new computer, you can transfer your Minecraft: Java Edition worlds, so you can keep building without starting over. If you have not exported a backup file of your world to transfer, visit Save a Backup of Your Minecraft: Java Edition World to learn how.
- Copy the zipped backup file to your new computer and unzip it.
- Move the folder containing the unzipped world folder into your Minecraft saves folder on the new computer.
- Windows: %appdata%\.minecraft\saves
- macOS: ~/Library/Application Support/minecraft/saves
- Launch Java Edition.
- Select Singleplayer. Your world will now appear as a playable option.