Maria Tzanetakou alerts us to an issue with sheet sets that are created in one version of AutoCAD, then used in an older version.
"Let's say that you create a DST file called A, using AutoCAD 2012. When you open a drawing that is included in this A.DST file, the A.DST automatically appears and opens. This makes it easy to check all the drawings and subsets you have created.
"If you try to open the same file using AutoCAD 2011, however, the A.DST will not automatically appear and open."
Notes from Cadalyst Tip Reviewer Brian Benton: I tested this in various versions of AutoCAD and found that it worked sometimes, but not every time. One should always be careful when working in an environment in which different versions of AutoCAD (or any program) are used. Some functions of a program are backwards compatible, but other items may not be. A case in point is Civil3D: Civil3D objects do not work in older versions. AutoCAD often is the same, especially in more complex tools like sheet sets.