Below is an actual error captured in SQL Server Error log during an incident.
This error is not quite accurate because it says SQL Server must shut down in order to recover a database which is database id 1. In SQL Server, database id 1 means "master" database. The next statement says the database is either a user database or system database. In this particular case, it can not be a user database.
The error message is quite generic. It appears that SQL Server does not change the error messages depending on the database id in this case, maybe it could be due to a performance impact.