You receive an error message when you open a SharePoint Online custom audit report

When you open a Microsoft SharePoint Online custom audit report, you experience one of the following symptoms:

• When you open custom audit report in the Microsoft Excel Web App, you receive the following error message:
  Couldn't Open the Workbook
• When you open the custom audit report in the Microsoft Excel client, you receive the following error message:
  Excel found unreadable content in <file name>. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes.
  Note In this message, the placeholder <file name> represents the name of the file that you're trying to open.�

To work around this issue, download a local copy of the file, open the file in Excel, and then select Yes to repair the file when you receive the error.

If you want to store the file on a SharePoint Online site, repair and save the file, and then upload the file to the SharePoint Online site.

This issue occurs if the following conditions are true:

• You received the most recent SharePoint Online service update.
• Incorrect formatting exists in the table.
  
  Note No data is lost when you receive these error messages.

Still need help? Go to the Office 365 Community website.