Transposition greyed out for no sharps or flats

When attempting to transpose from ‘C major’ to any other key the transpose box is greyed out. Thus, one has to insert an initial key signature before transposing.
What is the logic behind this inconsistency?

It works for me. What are you doing exactly?
Here are my results (screenshots):

The initial state goes from C to C# before clicking the “Apply” button.

The final state goes from C to C# after clicking the “Apply” button.

The result after clicking “OK”

I’ve been working on Dorico 3.5 files updated to Dorico 5. Choral editions. Those modally requiring no signature when transposed won’t allow me to simply transpose.
Is this another example of layouts not allowing certain things through?
If the work originally has a flat or sharp key signature there is no issue.

By the way - there’s hardly ever a key signature other than one flat during this period.
During the period certain composers would ‘place’ the voices lower than they would actually be singing to keep the ranges on the staff rather than creating ledger lines. This explains some unusually low bass and treble parts.

You should show signposts to find out if your initial key signature is C-major or an atonal key. See the first screenshot in my reply. If it’s atonal then the transpose dialog really has nothing to go on as far as the key signature is concerned.

How an atonal score will look. Note that the ‘transpose key signatures’ choice is greyed out.

This is the result of following though with the steps outlined in my first reply.

By the way, Gesualdo is one of my favorite composers.

It is possible that years ago I had input the score as ‘atonal’ . As the only likely accidentals would be b flats, c sharps or f sharps to avoid the mi-fa problem of modal music it would be unlikely for me to notice of that were the case.
At present I’m working on a motet that doesn’t have the issue.
I did have the problem yesterday which I resolved by adding the key signature and then transposing. It worked. I have a musica ficta workaround that still requires me to go through the work methodically to make any adjustments as they don’t happen automatically. One of the things I am waiting for Dorico developers to add to the programme.

I have edited all his religious repertoire and a substantial part of this madrigals over the years and my choir has performed all his religious repertoire and a vocal ensemble I directed presented this last three books of madrigals years ago.

Note all the differences between

  • C major
  • A minor
  • atonal or “open” key, and
  • no key signature

… all of which show no accidentals, but function differently in Dorico. Fortunately if you transpose a score that lacks a key signature, you can still add the correct one afterward with no harm.

As I have discovered.