Maintenance Plan Problem

A vendor installed SQL Server 2012 Express on a Windows 2016 Server box.  We did a version upgrade to 2012 Standard Edition to access the Maintenance Plan management option.

I can create a Maintenance plan, but if I try to modify it I get an "Object reference not set to an instance of an object. (Microsoft.DataTransformationServices.VsIntegration) error.  What causes this, and how do I correct it?

Thanks for your help!