If you receiving the warning "Excel was able to open the file by repairing or removing the unreadable content" when opening an export from ActivityInfo in Microsoft Excel, it is likely because your form contains a multi-line text field with more than 32,767 characters.
You can allow Excel to "repair" the file by truncating text that is longer than 32,767 characters by clicking the Close button.
If you need access to the full text contained in the field, you can open the file in another spreadsheet program with larger character limits, such as: