ERROR 000539: Error running expression:rcexec ()

What is error 000539 file expression?

The error occurs because the output value of the iterator is used as an expression rather than an inline variable in the Calculate Field tool. The tool has two outputs: Selected Features and group Value of the field for selected features, which could be used as an inline variable in other tools.
 

What is error 000539 in Python?

This issue occurs if the field referenced in the Python expression does not exists or is misspelled. In this example, the ‘Number_of_Interns’ field is misspelled as ‘Number_of_Intern’ in the expression. The correct field name is ‘Number_of_Interns’ as displayed in the attribute table below.