A particular client had an issue exporting a report to Excel and got the following Excel error:
“An Unexpected error has occurred”
The following error message appearing during the loading of the file in Excel.
This is a generic SharePoint issue and can be resolved directly in Excel.
For Microsoft Excel 2010 onwards:
This should resolve the issue. If you are still experiencing problems with opening the file in Excel, please reach out to firstname.lastname@example.org.
I hope this helps!