Здравствуйте,
Это бывает со всеми
excel
файлами, или только с некоторыми?
Посмотрите и в каком режиме работают у Вас
Web
Apps?
Office Web Apps licensing offers two options:
View-only. By default, Office Web Apps is view-only. View-only functionality is provided
for free.
Edit and view. You must purchase an editing license to use the editing features of Office
Web Apps with SharePoint 2013. You enable editing when you create the Office Web Apps Server farm.
Overview of Office Web
Apps and how they work on-premises with SharePoint 2013