Rated 5 out of 5 stars

oops, the tags where cut, not escaped.
the right code (without "special" symbols):
em:targetApplication !-- Thunderbird --
Description
em:id {3550f703-e582-4d05-9a08-453d09bdfdc6} /em:id
em:minVersion 0.6 /em:minVersion
em:maxVersion 1.6 /em:maxVersion
/Description
/em:targetApplication
and replace "em:maxVersion 1.6 /em:maxVersion" with "em:maxVersion 2.0.0.* /em:maxVersion"