Parameter Sweep: Create Models not working? This fixed for me (Legacy FEKO)

I hope this will help someone stuck in the same situation. Error messages were not fully helpful.

I was running Legacy CADFEKO and when trying to Parameter Sweep and solve for a range of a variable, I got:

"Invalid Workflow" "Not all files that are required for this model could be found".

I had previously checked the "To the Feko *.out file" option

After unchecking this option (under the Run/Launch settings), I could parameter sweep again!