nopSolutions/nopCommerce · critical · Exception

ConnectionStringWrongFormat

Error message

ConnectionStringWrongFormat

What it means

Thrown during installation when the resolved connection string is null or empty. The installer either uses the user-supplied raw connection string or builds one via dataProvider.BuildConnectionString(model); if the result is empty, nopCommerce cannot proceed to save DB settings.

Source

Thrown at src/Presentation/Nop.Web/Controllers/InstallController.cs:217

        {
            if (!_fileProvider.FileExists(file))
                continue;

            if (!_fileProvider.CheckPermissions(file, false, true, true, true))
                ModelState.AddModelError(string.Empty, string.Format(_locService.Value.GetResource("ConfigureFilePermissions"), CurrentOSUser.FullName, file));
        }

        if (!ModelState.IsValid)
            return View(model);

        try
        {
            var dataProvider = DataProviderManager.GetDataProvider(model.DataProvider);

            var connectionString = model.ConnectionStringRaw ? model.ConnectionString : dataProvider.BuildConnectionString(model);

            if (string.IsNullOrEmpty(connectionString))
                throw new Exception(_locService.Value.GetResource("ConnectionStringWrongFormat"));

            DataSettingsManager.SaveSettings(new DataConfig
            {
                DataProvider = model.DataProvider,
                ConnectionString = connectionString,
                Collation = model.Collation,
                CharacterSet = model.CharacterSet
            }, _fileProvider);

            if (model.CreateDatabaseIfNotExists && !await dataProvider.DatabaseExistsAsync())
            {
                try
                {
                    SetProgressMessage(_locService.Value.GetResource("Progress.CreateDatabase"));
                    dataProvider.CreateDatabase();
                }
                catch (Exception ex)
                {

View on GitHub (pinned to 64bdf2ff08)

Solutions

1. Provide a valid connection string. For raw mode use the provider-correct format (SQL Server: 'Server=...;Database=...;User Id=...;Password=...;Trusted_Connection=True;').
2. For non-raw mode, fill all required fields (Database server, Database name, credentials) so BuildConnectionString succeeds.
3. Verify the selected DataProvider matches the connection string format (SQL Server vs MySQL vs PostgreSQL).

Example fix

// before
var connectionString = model.ConnectionStringRaw ? model.ConnectionString : dataProvider.BuildConnectionString(model);
if (string.IsNullOrEmpty(connectionString))
    throw new Exception(_locService.Value.GetResource("ConnectionStringWrongFormat"));

// example valid SQL Server connection strings:
// Server=tcp:localhost,1433;Database=nopCommerce;User Id=sa;Password=Your_password123;Encrypt=false
// Server=localhost;Database=nopCommerce;Integrated Security=true;TrustServerCertificate=true

// Validate the connection string format before saving
var connectionString = model.ConnectionStringRaw ? model.ConnectionString : dataProvider.BuildConnectionString(model);
if (string.IsNullOrWhiteSpace(connectionString))
{
    ModelState.AddModelError("", _locService.Value.GetResource("ConnectionStringWrongFormat"));
    return View(model);
}

catch (Exception exc) when (exc.Message == _locService.Value.GetResource("ConnectionStringWrongFormat"))
{
    ModelState.AddModelError("ConnectionString", exc.Message);
    return View(model);
}

When it happens

Trigger: User submits the install form (InstallController line ~217) with an empty/malformed connection string (raw mode) or form fields that BuildConnectionString cannot turn into a valid string (e.g. missing server/database in non-raw mode).

Common situations: ConnectionStringRaw=true but the field left blank; required DB fields (Server, Database, Username, Password) omitted so BuildConnectionString returns empty; a custom data provider's BuildConnectionString has a bug; copy-paste introduced whitespace/hidden characters.

Related errors

• Data provider supports connection only with login and passwo
• Data provider supports connection only with login and passwo
• DatabaseCreationError
• DatabaseNotExists
• Unable to connect to the new database. Please try one more t

AI-assisted analysis of nopSolutions/nopCommerce@64bdf2ff08 (2026-08-13). Data as JSON: /api/errors/49f7cf2162ba17b9. Report an issue: GitHub.