I’m sorry you’re in this position, Wemmbu FlameFrags.
I know how frustrating it is to lose access to your Microsoft account, especially with Minecraft linked to it. Just to make sure I have a correct understanding of the situation, can you please confirm:
- Was this a personal Microsoft account that used your school email address as its sign-in address? Or was it an organizational account directly managed by your school?
- When you say you "can no longer sign-in," is it because the deactivated school email was its verification method? Or the account does not exist? Or the password is rejected?
- If it requires a verification code from the old email, did you previously add a phone number, recovery email, Authenticator, or another verification method to the account?
If it's just an alias, you don't actually need to activate it to sign into your Microsoft account. We just need to deal with what's stopping you from signing in. However, if it's also a verification method, especially if it's the only one, the situation is much more complicated.
The best option would be to ask your previous school whether they can temporarily restore/recreate that mail address, or otherwise help you regain access to the mailbox. Use that chance to add new verification methods and change the current alias to a new available one.
If you cannot get into contact with them, or the address cannot be recovered, try the Sign-in Helper. It'll identify your account issues and, based on detected situations, offer options to contact support staff. You may be presented with the Microsoft Account Recovery Form where you can provide the evidence.
Recovering access to your Microsoft account is the most important thing to do here. However, I must also be realistic with you so you can have correct expectations moving forward:
- Microsoft Q&A is a user-to-user support forum. Contributors cannot access account information, restore a Microsoft account, or recover a license under it.
- No one can manually review your evidence to recover your account, even Microsoft Support. Microsoft prohibits its customer service from modifying account information.
- License/subscription cannot be transferred to another Microsoft account. A Minecraft: Java Edition license is permanently associated with the account that purchased or redeemed it.
I know this is not the answer you're hoping for, but I think it's better to be truthful. If the account cannot be recovered, you should be prepared for the possibility that access to that Minecraft license may also be lost with it.