I have a bunch of plots to make and encountered the same problem.
I've been trying to do exactly the same and tried both: set(0,'defaultAxesXlabel','MyLabel') set(groot,'defaultAxesXlabel','MyLabel').
Gives my exactly the same problem.
Error using axes While setting the 'Parent' property of 'Axes': Value must be a handle.
Error in subplot (line 481) ax = axes('Units', 'normalized', 'Position', position, ...
R2015b
Anyone who knows the problem?