Co-authoring simplifies collaboration by enabling multiple users to work productively on the same document without intruding on one another�s work or locking one another out. This functionality requires no additional server setup and is the default state for documents stored in SharePoint 2010.
Co-authoring is easy to use from the end user�s point of view. When a user wants to work on a document in Word 2010, PowerPoint 2010, or OneNote 2010, he or she merely opens it from SharePoint , as usual. If another user already has the document open, both users are able to edit the document at the same time; access to the document is not blocked and no error appears
In Word 2010 and PowerPoint 2010, saving to a document notifies other users viewing the document that there are new edits. Those users can refresh their view immediately to see those changes or continue their work and refresh later to see the latest edits. The authors can also see one another�s work, and everyone knows who is working on the document. SharePoint 2010 versioning and tracking tools protect the document so that authors can roll back unwanted changes.
Note:
- When a user checks out a document for editing, this locks the document for editing to only that user, which prevents co-authoring. Require Check Out should not be enabled in document libraries where co-authoring will be used. By default, Require Check Out is not enabled in SharePoint 2010. Users should not check out documents manually when co-authoring is being used.
- To collaborate best in PowerPoint and Word, we recommend that all users work with Office 2010
How to do this
1 Open document from SharePoint
2. Open from local client - > Edit
3. Enter your credentials
And start making changes..