How to resolve this in SSMS TITLE: Cannot connect to (localdb)\MSSQLLocalDB

Check if the SQL Server (MSSQLSERVER) service is running in services.msc, try connecting using the server name instead of (localdb)\MSSQLLocalDB, or reinstall LocalDB.

Related articles:

Troubleshooting Guide: How to Fix "Cannot Connect to (localdb)\MSSQLLocalDB" Error in SSMS
When working with SQL Server Management Studio (SSMS), you might encounter the "Cannot connect to (localdb)\MSSQLLocalDB" error message. This can be frustrating, especially if you need to access the database to perform important tasks. Fortunately, there are several troubleshooting steps you can take to resolve this error message and get back to work.

Resolving Connectivity Issues with (localdb)\MSSQLLocalDB in SSMS: A Step-by-Step Guide
If you are trying to connect to a SQL Server instance named (localdb)\MSSQLLocalDB in SQL Server Management Studio (SSMS) and are facing connectivity issues, don't worry. You are not alone. The good news is that there are some easy steps to resolve this issue.

SSMS Error: Cannot Connect to (localdb)\MSSQLLocalDB - Here's How to Get Past It
Microsoft SQL Server Management Studio (SSMS) is a popular tool used by developers and database administrators to manage SQL Server databases. However, one common error that people face when trying to connect to a local SQL Server database through SSMS is the "Cannot Connect to (localdb)\MSSQLLocalDB" error message. This error can be frustrating, but there are several ways to get past it.