Originally Posted by
Polecat
Not everything works perfectly in MuseScore, but given that it is freeware, I think it is a fantastic tool and have been using it for years.
One workaround is to use the up/down arrow keys and the key signature tool - for example, if you wanted to transpose down a fifth, from G to C, say, then you would mark the entire score with ctrl. A, then hit the down arrow key seven times, shifting the entire notation seven semitones down. Then using the key signature tool, change the key from G major (one #) to C (no #). It's slightly longer, but up till now, it's always worked for me. I hope it does for you.