Error No 01556 appears when trying to Attach a
Flow Process to another Flow Process.
Error No: 01556
Objects from non-Workflow managed class '<Class_Name>' cannot be attched
to process.
This error can occur because the Flow
Process class does not have the WorkFlow Mechanism assigned to it.
Adding the WorkFlow Mechanism to the Flow
Process class is accomplished in the Data Model Designer.
Before doing this please make sure that you have
a good backup of your database.
Open Data Model Designer
Select File > Modify Database Structure
Then select your database and click OK
Click Yes to the prompt about making a backup of
the database
Login with an Admin user
Once it has finished loading the database then
click Next and then you will be on the Class Browser page
Select the Flow Process class and then you will
be able to add the WorkFlow Mechanism from the list
Then click Create and go through the rest of the
prompts