Cannot save report to XLSX, only XML, MHT or HTML (MAC and Office 2008)

Hello,

Subject nearly says it all, the problem is that I'm not the user but reporting for another user.

She uses MAC and Office 2008, when trying to save a report in XLSX format, this format is not available.

I saw that Paul advised another user to search the SDL community for this problem, but couldn't find any entry. So re-asking.

Many thanks in advance for your help.

Kind regards

JCB