Can two or more people edit an Excel document at the same time?

Question

I have a SharePoint 2010 site with a document library for storing Excel files. If someone is editing an Excel file (using stand-alone Excel, not Excel services), everyone else will be forced to open the file read-only until the first person is done editing. Is there a way around this? What I want is to allow two or more people to be able to edit the file at the same time. Also, I don't want people to overwrite each other. Instead, I'd like SharePoint to merge their changes. Is this possible in SharePoint 2010?

Answer 1

No, sadly:

The Excel 2010 client application does not support co-authoring workbooks in SharePoint Server 2010. However, the Excel client application does support non-real-time co-authoring workbooks stored locally or on network (UNC) paths by using the Shared Workbook feature. Co-authoring workbooks in SharePoint is supported by using the Microsoft Excel Web App, included with Office Web Apps

From Co-authoring overview (SharePoint Server 2010)

...and not for SharePoint 2013 either. Though it works for pretty much all other Office documents. Go figure.

Answer 2

The new version of SharePoint and Office (SharePoint 2010 and Office 2010) respectively are supposed to allow for this. This also includes the web based versions. I have seen Word and Excel in action do this, not sure about other client applications.

I am not sure about the specific implementation features you are asking about in terms of security though. Sorry.,=

Here is a discussion

http://blogs.msdn.com/b/sharepoint/archive/2009/10/19/sharepoint-2010.aspx