Minecraft suddenly says I don't own the game (PC)

Also…apparently when trying to login with the email it said he needs to migrate. But we’ve already done that (again, he’s been playing up until yesterday).

And he isn’t using the Xbox app just the Minecraft pc launcher. So maybe I do need to just deal with mojang and maybe not a Microsoft issue (tried going right to them as well and not this Xbox help line but cannot get anyone there either)

Sometimes their response can take up to 48 hours to arrive in your email address (don't forget to check spam/junk folder)

But just to double check everything from your side, you already tried everything from here:
https://help.minecraft.net/hc/en-us/articles/44...

Or all this together:
First uninstall actual minecraft launcher.

Open Settings, click Update and Security and then Windows Update;

Click Check for Updates;

Click the Download and Install Now option, if available (Install optional updates as well)

Also, check the Microsoft Store for any updates on the Xbox apps and its services and update everything too.

Now, sign out from your account on both Xbox app and Microsoft Store and do this:

Go to windows settings > apps > search for gaming services app > click on it and select advanced options.

After that, click repair and then reset

Then do the same for the Xbox app:

Go to windows settings > apps > search for Xbox app > click on it and select advanced options.

After that, click repair and then reset

Finally do this:

Step 1: Open the Run window by pressing Windows + R key.

Step 2: Input WSReset.exe in the Run window and click OK.

Step 3: Then a command prompt window will appear. After a few seconds, Windows Store will open.

Sign in again on both Microsoft store and Xbox app with your account , install minecraft launcher and give it a new try

Right?

This is Java edition. Yes to reaching out to mojang (or trying) but have not heard back

Yeah we looked at that. It tells us the account is already migrated.

Thank you for all your time and help.

Yes to trying all from that link.

Full disclosure- this issue is currently on PC but assume it is pretty close to the same as it occurring on Xbox.

My point being - issues on PC with a version purchased via pc years ago should have nothing to do with Xbox correct? Or because it is crossplay now and Microsoft, they are interchangeable and so the Xbox app can effect tye Minecraft launcher etc? (Kinda confusing now with MS owning and all the cross play). This one has never been played on Xbox. If that matters.