I am attempting a simple task of identifying structural breaks in a single time series trend.

There is a single dep var t=1994-2021, two variables in X viz. constant and time

The following error message comes up

The variable X is read-only
*** error in function SB_GUI, line 7
> list X = !nelem(X) ? null : X

Some guidance would be welcome

Brian, it looks like you're talking about or contributed package StrucBreak, and furthermore it seems to me you might be using an outdated version of it. Indeed, our changelog for the current version 0.91 contains the entry: "fix show-stopping problem in the GUI with the X list"

What's your installed version of the package? 

thanks

sven