The fix was simple: set the environment variable LOCALAPPDATA to a short path before starting the instance. Lena added it to the pipeline script and never saw the error again.
Lena nodded. “It’s mssqllocaldb . Microsoft’s best-kept secret. It doesn’t try to be a production database. It tries to be a developer’s shadow—always there, perfectly identical, and gone without a trace when you look away.” mssqllocaldb
She closed the terminal. The instance stopped itself after the last connection closed. No services. No leftovers. No ghosts. The fix was simple: set the environment variable
She opened a PowerShell window and typed: SqlLocalDB.exe info "CodeCraftBuild" “It’s mssqllocaldb
The pipe name appeared. She connected SSMS to it while a failing test was paused on a breakpoint. Inside the database, an open transaction held locks. She could see them. She could kill them. She could rewrite the query right there.