If while working on Azure SQL PaaS or even on-premise SQL database, you are stuck with this error “Index was outside the bounds of the Array. (Microsoft.SqlServer.smo)”, the most likely reason is that the version of SQL server management studio on your local machine is on the lower version that the SQL server version on the server end.
In such a scenario, you would need to upgrade the SSMS version installed on your local machine. Apparently, the reason behind the error message is that SQL couldn’t show new features in your old SSMS version. Since SSMS is free now and is a separate product, it can be updated irrespective of the server version.