I once fixed this error manually, but it returned after a few days. The culprit turned out to be hidden corruption in the MDF file, which disrupted SQL connectivity. Repeated fixes were only treating the symptoms, not the cause. Finally, I used the DRS SQL Database Recovery Tool, which deeply scanned the database, fixed corruption, and restored all components — tables, triggers, and stored procedures — ensuring the error didn’t reappear again.
Read More: Fix SQL Server Error 40
Read More: Fix SQL Server Error 40