I have a time signature change in my piece to 6/4 from 4/4 for one bar before it returns to 4/4. For all bars there is a rest except for percussion which has 2 beats. It then shows 2 rests rather than 4. All other bars are showing the correct number of rests.
I’ve deleted the entire percussion line and added and removed the time signature change but it still only allows 4 beats in the bar.
I’m sure I’m missing something simple but I can’t figure out what I’m doing wrong. Any assistance would be greatly appreciated.
Dorico doesn’t automatically insert extra beats when you change the time signature - it ‘reformats’ bars so barlines are in the right place up to the next existing time signature or the end of the flow. The benefit of this is you don’t unexpectedly get gaps between existing notes, but the caveat is you can end up with bars that don’t add up to the time signature.
The easy way to fix this is to have Insert mode on (in Write mode, press I or click the I-like button in the toolbox on the left) when inputting time signatures - this tells Dorico to insert extra beats if necessary to have full bars.
As to fixing the existing problem, select something where you want the extra two beats to be inserted, then type Shift-B 2q Enter. This will tell Dorico to add two quarters/crotchets.
Basically Dorico is saying “Hey, if you want a different number of beats in a measure than is indicated by the time signature, you must know what you’re doing”. This mismatch between beats in a bar and the time signature can also happen if you mistakenly delete a bar line. It would be nice if Dorico could somehow flag these situations - it would have saved me from an embarrassing situation in a rehearsal. 
