Tools like the Fallout Shelter Save Editor allow you to upload your .sav file, edit it in your browser, and download the modified version.
Inside are container.[number] files — you need to find the largest one (the actual save). Copy it out and rename to Vault1.sav . save editor fallout shelter
👉
C:\Users\[YourUsername]\AppData\Local\Packages\BethesdaSoftworks.FalloutShelter_[random]\SystemAppData\wgs\ Tools like the Fallout Shelter Save Editor allow