Category: Troubleshooting

🚨Part of the SQL Server Errors series, the exact messages and what actually causes them.In: Security Msg 15023  ·  Level 16  ·  State 5 User, group, or role ‘AppUser’ already exists in the current database. Msg 15023, Level 16, State 5 ⚡Do not drop the user. ALTER USER [name] WITH LOGIN = [name]; remaps it…

🚨Part of the SQL Server Errors series, the exact messages and what actually causes them.In: Security Msg 4060 / 4064  ·  Level 11  ·  State 1 Cannot open database “YourDb” requested by the login. The login failed. Login failed for user ‘DOMAIN\user’. Msg 4060, Level 11, State 1 ⚡Check three things in order: the database…

🚨Part of the SQL Server Errors series, the exact messages and what actually causes them.In: Backup & Recovery Almost everyone meets this the first time they back up to a network share, and almost everyone spends the first ten minutes checking the wrong account. Msg 3201  ·  Level 16  ·  State 1 Cannot open backup…

🚨Part of the SQL Server Errors series, the exact messages and what actually causes them.In: Security The connection reached the server’s port and then died before the login was ever read, so the password is not the problem and there will be no 18456 in the error log. TCP Provider  ·  error: 0 A connection…

Every entry here is a message somebody pasted into a search box while something was broken. This page exists to get you from that message to the cause quickly, which is a different job from explaining what SQL Server errors are in general. Three Steps From Message to Cause 01 Get the real message The…

Get Collation Conflicts and Cross-Database Dependencies finds real collation mismatches, but assumes you already know what collation actually controls. This post covers the fundamentals directly: what changes with collation, a real case-sensitivity test, and the cross-database trap that script exists to catch. What Collation Actually Controls Collation determines two things for character data: sort order…

Reading and Fixing a SQL Server Deadlock and Troubleshoot SQL Server Blocking both point at isolation level as part of the fix without covering what the levels actually are. This post fills that gap: what each isolation level trades off, what Read Committed Snapshot Isolation (RCSI) actually changes, and a real check of where this…

SQL Server error 1934 means the connection running the write has the wrong SET options for a filtered index or indexed view. Reads still work, which is why it usually shows up as one failing job.

SQL Server has had JSON functions since 2016, and SQL Server 2025 added a native JSON data type on top of them. Most write-ups explain the syntax; fewer show what actually differs between storing JSON as text and storing it as the native type, or when reaching for JSON in a relational database is the…