LocalDB

Installing Microsoft LocalDB

Microsoft is no longer shipping separate MSI file for LocalDB it has to be installed either through Visual Studio installer or through SQL Server installer only.

If the default instance is not running properly, none of the repair steps will work and might not work even after reinstalling everything from scratch! Better create another instance as shown below:

Check running instances

SQLLocalDB info

Start an instance

SQLLocalDB start <instance_name>

Create a new instance

SQLLocalDB create MyInstance
SQLLocalDB start MyInstance