Migrating Mojang account to Microsoft deleted my Minecraft single player saves

I just had the same issue, so I don't believe this is an isolated incident.

If I figure anything out I'll reply here again.

Thank you for contact us! I'm Anderson, an Independent Consultant and a Microsoft user like you.

Good afternoon

The most likely thing is that it is a bug, unfortunately, because this is not common.

Hello Wayne Lau1，



Welcome to the Microsoft Community.

Mojang accounts were migrated for a period of time with the aim of moving all players' Minecraft accounts under Microsoft accounts. This migration process involved transferring data and game information related to Mojang accounts to the new Microsoft account system. During the migration, players will receive detailed instructions and steps on how to perform the migration via email. This means that during the migration process, players only need to follow the guidelines to seamlessly transfer their Minecraft game progress, purchase history, and other account information to their Microsoft account.



However, with the passage of time, the deadline for Minecraft account migration has ended and new Mojang account migration requests are no longer being accepted. In other words, you will no longer be able to log in to Minecraft using your old Mojang account. all players must access and log in to Minecraft through their Microsoft account. as a result of this change, any players who have not completed the account migration will no longer be able to continue to play with their original Mojang account.



In order to continue playing, you will need to log in to Minecraft with a Microsoft account, and if you don't already have a Microsoft account, you can easily create one and associate it with your Minecraft game. Note that the only way to purchase Minecraft is through a Microsoft account, so if you wish to repurchase or continue using Minecraft, it is recommended that you purchase and use a Microsoft account to play the game.



To summarize, with the migration process complete, Microsoft accounts are now the only way to log in to Minecraft. We recommend creating and using a Microsoft account to purchase and log into Minecraft as soon as possible.



You can also contact the support staff of the corresponding game to find out why.



Best regards

|Microsoft Community Support Specialist

Hi Антонио. My name is Kyle and I'm an independent advisor.

Thank you for posting on the Xbox Communities Forum. In early 2021, Mojang started the process of migrating Mojang accounts to Microsoft accounts. This was done as Microsoft's account system is more secure, and to make it easier to sign in.

This migration period ended on September 19, 2023. To ensure all your Minecraft account data transfered to your Microsoft account, you had to migrate your account before this date. However, players were given another chance to transfer their Minecraft license to a Microsoft account via the post-migration process.

The post-migration ended on December 18, 2023, and it is no longer possible to sign in with a Mojang account or migrate to a Microsoft account. If you did not migrate your Mojang account to a Microsoft account before December 18, 2023, I'm afraid you will need to purchase Minecraft again using your Microsoft account. I apologise for any inconvenience caused by this.

Please reach back if you have further questions.

Thanks,
Kyle

If you think you have migrated your Mojang account to the wrong Microsoft account you have to speak to Mojang support to reverse this. That's what they themselves say in the FAQ they published about migration. I also recommend checking your other Microsoft accounts and in Minecraft launcher delete all accounts and re-add your Microsoft account again.