Assume that you launch Microsoft SQL Server 2016 or 2017 Integration Services (SSIS 2016) package by using the common language runtime (CLR) stored procedure. When you run the CLR stored procedure which calls the SQLContext.WindowsIdentity property, you may notice that the SQLContext.WindowsIdentity property returns a NULL value for impersonated calls in SQL Server due to which the SSIS package does not start. This issue occurs if the CLR procedure is owned by a user who has a Windows login (not a SQL Server login) that does not have the SYSADMIN permissions. Additionally, you may receive an error message that resembles the following:
The operation cannot be started by an account that uses SQL Server Authentication. Start the operation with an account that uses Windows Authentication.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.