File Menu - "File Merge Preferences..."

There are two things you must consider when merging files.

The first is the option to "Merge Only" vs. "Merge and Decode."  Most often you will want
to keep "Merge and Decode" selected, but you might choose to select "Merge Only"
for merging any number of text files, such as mail files for organizational or archiving
purposes.

The second item specifies the method to use when uudecoding during a file merge. 
You may choose "Smart Decode" or "Super Smart Decode."  This item has no effect if
the "Merge Only" option is selected in the first section.