During installation, a file viewer should ensure that entries exist in the registry that accurately associate a file with the class identifier of the file viewer's in-process server DLL. The file viewer's installation program may merge the contents of a registration (.REG) file into the registry. A file viewer can register itself for more than one file type if it can handle multiple file formats. If a file type has more than one registered file viewer, the shell activates the most recently registered viewer for the file type when the user chooses the Quick View command.