The Minecraft launcher will load and offer to log in with the Mojang or Microsoft accounts. While the Mojang option allows a password entry, it tells me that as my account has been migrated it will no longer work.

When I attempt to access the Microsoft account, it remains on the splash screen and a red popup occurs in the top right corner which says 'Something went wrong in the login process'. I have uninstalled and reinstalled, scanned and restarted my laptop, and nothing has changed. Rolling back to a Windows 7/8 launcher also had no effect, as I still received the same error message when attempting my Microsoft account.