Halion play back not working on some notes

Hi. I have recently upgraded from Dorico Elements to Pro 3. I have a piece of music I am composing, which I began in Elements, but once I opened it in Pro 3, a few random notes in different instruments do not sound when playing. I really can’t figure out why. Say the first two quarter notes of a certain bar for the cello will sound but no notes in the next measure will, then maybe one will in the next. I changed the voices from Halion basic to HSO. I also noticed a few instruments in which I used in Elements seem to be gone in Pro. Maybe I just can’t find them. The main one that’s missing is the timpani. I know that must be an instrument in Halion. Any help would be greatly appreciated.

Do you maybe exceed the tone range of some instruments? The sounds in Dorico Elements you can usually play over the full range (regardless how awful that might sound), but the HSO sounds are limited to the natural range of the respective instrument. If you open the HALion Sonic SE editor window (in Play Mode) you can see the ranges of the instruments. Click on one of the slots in the left list and check the virtual keyboard on the bottom of the window.

Also, when you changed the playback sounds to HSO, did you also change the Playback Template to reflect the switch?

Yes, every instrument is in a comfortably playable range. Derrek, I had not switched the playback mode to reflect HSO and Pro. Once I did this everything began working perfectly. Even the Timpani is playing again. Thank you!