For Umbraco 13 I am using this for my connection string:

"ConnectionStrings": {
    "umbracoDbDSN": "Data Source=|DataDirectory|/Umbraco.sqlite.db;Cache=Private;Foreign Keys=True;Pooling=True",
    "umbracoDbDSN_ProviderName": "Microsoft.Data.SQLite"
  },

However when I start with

dotnet run

, I get:

[14:17:26 WRN] Configured database is reporting as not being available.
Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 14: 'unable to open database file'.

The folder

umbraco/Data

is fully writable. How do I make sure the database exists?

If a connection string is set it skips the installer, so if it is your first run of the site you need to either have a connection string and unattended install set up, or have no connection string and then just set it via the installer

aha, the more you know, thanks! that solved it