The following error message occurs during an ECS error check:
"ERROR:SchematicEditor - Net "<bus_name>" Some nets have similar names which make this name illegal. For example, a net named "A" would make a name like A(0:3) illegal."
This error is issued for two bus segments that have the same name but different indexes (i.e., mybus(0:3) and mybus(4:7)).
To fix the problem, add a full version of that bus to the sheet. For the example above, create a bus named "mybus(0:7)." It is not necessary to connect the new complete bus to any components.