MATLAB Error - Warning: Executing startup failed in matlabrc. In matlabrc at 212

After reinstalling MATLAB I saw the following error:

Warning: Executing startup failed in matlabrc.
This indicates a potentially serious problem in your MATLAB
setup,
which should be resolved as soon as possible.  Error detected
was:
MATLAB:FileIO:InvalidFid
Invalid file identifier.  Use fopen to generate a valid file
identifier.
> In matlabrc at 212 

This was due to a problem in my "startup.m" file which was still persistent from a previous installation, which tried to load a toolbox that was no longer installed. This was located in the following folder:

%UserProfile%\Documents\MATLAB

As I had no files there that I needed, I renamed the folder to MATLAB_old, then tried opening MATLAB again. This time it started up fine so I deleted the folder completely as it is not needed for my version (R2012a).