readtable giving problems when reading excel file in Matlab

Question

I'm reading a very small excel table in Matlab by running:

mytable=readtable('myexcel.xlsx');
mytable

When I open Matlab and run this, it runs perfectly. When I run it again, it always returns a pop-up: File In Use:

I noticed in the task manager that EXCEL.EXE processes accumulate as I run this code. Closing all of them solves the problem.

Is this a file-handle problem? What am I missing? Is there any way to "close" the excel file in this case?

Edit: I'm running Matlab R2016b in Windows 7 Professional. Microsoft Office Pro Plus 2013.

Thanks