This is a continuing story, isn't it? (Note to other users: bh_perl has written a few earlier threads on processing this or very similar data.)

Anyway... must this be a regular expression? Id' rather use split.

    s/\s+$//;  #remove trailing whitespace -- and newlines!
    my($name, $value) = split /\s*:\s*/, $_, 2;
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The 2 as a third argument to split prevents the value from getting broken up in case it contains a colon, as split now always will split into two parts: the name, and the value.