GUI error problem on starting, but no changes to code

Hi,

I've been running a fairly complex GUI I created, and it was working fine until I pressed a button while a waitbar was running. I closed the GUI and tried to start again.

Now everytime I try to open the fig file in guide I get the error

Error using gui_mainfcn (line 41)
Could not find field 'gui_OutputFcn' in the gui_State struct in GUI

When I try to run the fig file I get

Error using guy_mainfcn(line41)
Could not find field 'gui_OutputFcn' in the guy_State struct in GUI MATLAB-file IDIF.m

Error in IDIF(line 45)
guimainfcn(gui_State, varargin{:});

Error in guidefunc>layoutActivate(line 1157)
feval(fcn)

Error in guidefunc(line 13)
varargout=layoutActivate(varargin{:});

Does anyone have any idea how this might have happened, even though I have not changed anything in either the .fig or .m file? I've restarted Matlab and my computer many times but I still cannot run my code

Thanks, Jim

[Jan]

You cannot expect, that someone can suggest a bugfix without knowing the code. The error message seems to be clear: The struct gui_State is incomplete. But it is impossible to guess why.