<File> is not a text file

Although most VSS commands work on either text or binary files, this command does not. This error has the following cause and solution:

• You attempted to execute a command that operates only on text files, such as View File on the Edit menu or Find In Files on the Tools menu.

  Binary file types are set either automatically by VSS or manually using the File Types tab in the SourceSafe Options dialog box on the Tools menu.