This command operates on only one item

For many VSS dialog box lists, you can select more than one item at once, and then act on all the items together. However, some actions cannot operate on more than one item at a time. This error has the following cause and solution:

• You selected more than one item and then applied a command that operates on only one item at a time. For example, you may have tried to use the View command, which works with one file at a time.

  Press the space bar on an item to make it the only item selected in the list.