Actually using version 2018.2.6 but this error just started happening.
Activity: Append Range (Workbook)
I have the file path as a variable and am trying to append to a .XLSM file. The error that keeps coming is
Systems.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
If I change the file path to append to a .XLSX file, error does not come up. Up until now, append range was working with .XLSM files (although you can’t use the file explorer to search for them in the activity).