If you can access your old email address:
If you log in with your username, you can migrate your Minecraft account to a Mojang account at https://account.mojang.com/migrate. You will need to enter your Minecraft username and password. Afterwards, the site will ask if you would like to continue using your old address, or if you would like to select a new one for use with your Mojang account. After making your choice, a verification email will be sent to your old address. You can now log into Minecraft, Minecraft.net, and Mojang.com with your email and Mojang password.
If you have already migrated your Minecraft profile to a Mojang account, you can change your email at https://account.mojang.com/me/settings.
If you have already migrated your Minecraft profile to a Mojang account, you can change your email at https://account.mojang.com/me/settings.
If you cannot access your old email address:
If you have not migrated your account, you have a typo in your email, or if for some reason you do not have access to your original account, locate the transaction ID or gift code from when the account was purchased, and contact customer support. Please provide the transaction ID, the old email, your new email, and we'll change it for you.
