We had a server crash. When the replacement was staged, we moved the SQL DB files (.mdf and ldf) to the appropriate SQL Server folder.
Connection via Windows Authentication works fine. The DB is visible as well as all of its tables.
However, when connecting via SQL Authentication, the connection is made and the DB shows in the list of databases. But when expanding the database to see the tables, the error:
"Database <db name> is not accessible. (Microsoft.SQLServer.Express.ObjectExplorer)"
I have checked all settings against other sites (each sites has its own SQL setup), and everything looks correct.