Deal with Matlab errors: Can't be saved as MAT file

Problem description:
When tring to save variable to .mat file, it failed and warning popups:
"Warning: Variable 'variable name' cannot be saved to a MAT-file whose version is older than 7.3.
To save this variable, use the -v7.3 switch. Skipping...".
But the actual version of the MATLAB is newer than 7.3.

Solution:
"save -v7.3 Test.mat Test". Try the format like this way.