Hi Dr. Spielberg,

Thank you for your prompt reply to my previous post!

I was wondering if any other users had received this error message when running the GTG preprocess GUI: 

Error using parpool (line 103)
Found an interactive session. You cannot have multiple interactive sessions open simultaneously. To terminate the existing session, use 'delete(gcp('nocreate'))'.

Error in GTG_preprocess_GUI>Start_pushbutton_Callback (line 2466)
parpool close %#ok
Error in gui_mainfcn (line 95)
feval(varargin{:});
Error in GTG_preprocess_GUI (line 153)
gui_mainfcn(gui_State, varargin{:});
Error in matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)GTG_preprocess_GUI('Start_pushbutton_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating UIControl Callback

I was instructed by another user to replace all instances of "matlabpool" with "parpool" in the GUI script, and I have tried shutting down any existing parallel pools by running this code before opening the toolbox: 
 

poolobj = gcp('nocreate');
delete(poolobj);

Do you have any suggestions?

Thank you so much!
Shaadee