An error has occured

Question

Hello community...I am new here and am seeking some advice.

Are there members who use Microsoft Excel Office? I was given an Excel file to do a simple change. But Excel won't let me save to .xlsx format.
After saving the file this error message occurred:
.xlsx file format is not valid
Also
An error has occured

The version of office is Microsoft Office 2016.

Is anybody able to help with this please?

MikeGilliam · Accepted Answer

This issue occurs only when you send a workbook for review. The workbook file is saved as an Excel binary workbook. However, the workbook has an .xlsx extension that is appended to the file. To work around this issue: how to fix Excel errors