Warning Message "unable to write to Excel format"

I'm solving a problem with variational inequality. I have a code but after 6 iteractions Matlab blocks and gives me this Warning:

Unable to write to Excel format, attempting to write file to csv format. To write to an

Excel file, convert your data to a table and use writetable.

What's the meaning?

[KALYAN ACHARJYA]

It would be helpful to answer, if you share the code or representational code?

[Rita Sciuto]

I sent you a message

Answer 1

[Jiajia]

I have encountered a similar problem. How can I sove it?

[Walter Roberson]

If you have a new enough version of MATLAB, change all of your calls to xlswrite() to be calls to writetable() or writematrix() or writecell(), passing in the 'UseExcel', false option. Also, change any xlsread() to readtable() or readmatrix() or readcell() with 'UseExcel', false . This will prevent Excel from being invoked to read of write the excel file.

Avoiding Excel can be important because historically the connection with Excel can sometimes get stuck with a file open as far as Excel is concerned, and then the file is busy when you go to write it. Sometimes this can occur if you do two xlswrite() to the same file in quick succession, as Excel does not necessarily finish flushing the file and closing it before it returns from the ActiveX connection that xlsread() and xlswrite() use on MS Windows machines with Excel installed.