diff --git a/reaction-mailcreate/createMails.py b/reaction-mailcreate/createMails.py
index 93a73c38becb43113f41fc1fbc86580338912334..acc78feef9472a7889ab1dd9e6b50a473669693f 100755
--- a/reaction-mailcreate/createMails.py
+++ b/reaction-mailcreate/createMails.py
@@ -55,7 +55,7 @@ parser.add_argument('-f', '--from',       dest='sender',     default='Nobody <no
 parser.add_argument('-F', '--force',      dest='force',      default=False, action='store_true', help='force insecure login without TLS/SSL (default: False)')
 parser.add_argument('-H', '--hashstring', dest='hashstring', default='{salt}{campaign}{infix}-{site}', help='string to be hashed for the URL (default: "{salt}{campaign}{infix}-{site}" where "{salt}" is a random string)')
 parser.add_argument('-i', '--input',      dest='input',      default='{basedir}/{campaign}/Input{infix}.lst', help='input file (default: "{basedir}/{campaign}/Input{infix}.lst")')
-parser.add_argument('-o', '--output',     dest='output',     default='{basedir}/{campaign}/{site}/Mail{infix}.txt', help='output file name template (default: "{basedir}/{campaign}/{site}/Mail{infix}.txt")')
+parser.add_argument('-o', '--output',     dest='output',     default='{basedir}/{campaign}/{site}/Mail{infix}.eml', help='output file name template (default: "{basedir}/{campaign}/{site}/Mail{infix}.eml")')
 parser.add_argument('-R', '--reply-to',   dest='replyto',    default=None, help='reply-to mail address (default: None)')
 parser.add_argument(      '--salt',       dest='salt',       default=None, help='salt to use for hashing (default: random 8-byte hex string)')
 parser.add_argument('-s', '--subject',    dest='subject',    default='Security Challenge for {site} -- {campaign}{infix}', help='mail subject (default: "Security Challenge Message -- {campaign}{infix}")')