By default, when creating a merge output
file (by use of the Save command on the File menu),
Diff Merge uses the same line termination characters as those that are in
the contributors to the merge.
Procedure
Click Edit > Properties.
In the Properties window, set an option in Output
Line Termination:
To retain the style of line terminators used in the contributors
when creating the merge output file, set Same as contributors.
To force the merge output file to have Windows line terminators,
regardless of the style used by the contributors, set Windows-Style
<CR><LF>.
To force the merge output file to have line terminators
that are used on Linux and the UNIX system, regardless of the style used by
the contributors, select UNIX-Style <LF>.