I got below message, when I'm doing the upgrades from 2.0 to 2.1, please help!
Setup failed: System.InvalidOperationException: Sequence contains more than one element at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source) at System.Data.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__3[TResult](IEnumerable`1 sequence) at System.Data.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot) at System.Data.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression) at System.Linq.Queryable.Single[TSource](IQueryable`1 source) at Nop.Services.Installation.InstallationService.InstallSettings() in F:\Own\NopCommerce\Sources\src\Libraries\Nop.Services\Installation\InstallationService.cs:line 4495 at Nop.Services.Installation.InstallationService.InstallData(String defaultUserEmail, String defaultUserPassword, Boolean installSampleData) in F:\Own\NopCommerce\Sources\src\Libraries\Nop.Services\Installation\InstallationService.cs:line 9150 at Nop.Web.Controllers.InstallController.Index(InstallModel model) in F:\Own\NopCommerce\Sources\src\Presentation\Nop.Web\Controllers\InstallController.cs:line 377