SharePoint document collaboration is a powerful feature. Co-authoring with two or more persons on a document allows you to work more efficiently. There are no doubts about which version of a document is the latest, current version.   One thing is important to know about SharePoint file collaboration: In SharePoint, files are “checked out” when you want to work on them. Whether it is an Excel file with multiple users, or a PowerPoint collaboration, there can only be one user actively working on the file at any time. This user needs to “check out” the file to work on it, and check it in after they are finished. This prevents any synchronization problems.