Field 'probe_axis' not found when loading new spectra replacing an old dataset

Callback:

Error using rmfield (line 62) A field named 'probe_axis' doesn't exist.

Error in lineshape_analysis>btnLoad_Callback (line 150) handles = rmfield( handles, 'probe_axis' );

Error in gui_mainfcn (line 95) feval(varargin{:});

Error in lineshape_analysis (line 46) gui_mainfcn(gui_State, varargin{:});

Error in matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)lineshape_analysis('btnLoad_Callback',hObject,eventdata,guidata(hObject)) Error while evaluating UIControl Callback.