Hello Daniel,
What version is reported by the About command in the Help menu?
I was aware of a similar problem for version 2.3, but I thought I had fixed it. And I had tested the updated from 2.2 to 2.3.1.
A work-around for this problem is to completely redownload your purchased copy of Composer, following the instructions at
www.notation.com/redownload.htm
Cheers
-- Mark