SYMPTOM:
In Strategy Web, 'Excel found unreadable content in 'xxxx.xlsx'.' message is displayed when opening the exported Excel file in Microsoft Excel 2007/2010, as shown in the image below:

STEPS TO REPRODUCE:
Follow the steps below to reproduce the issue with Strategy Tutorial project:

CAUSE:
This is a known issue with Strategy Web.
ACTION:
Contact Strategy Technical Support for an update on the status of this issue.