EastWest Opus and Play 6 don’t work well for me directly in Dorico.
My solution is to either roll back to Play 5, or run the VST2 versions of Opus or Play6 inside Bidule instances.
I’ve run the 5.0.1 version through some tests with good results (word-builder for choirs and such worked too). I think the major difference between the two is that the 5.0.6 one includes a VST3 variant as well (which I have not had a chance to test yet). Might need to be white-listed in Dorico’s plugin settings.
Here are some links to Play 5.
Play 5.0.1 Link is: http://software.soundsonline.com/Products/PLAY/Play_5.0.1_Win.zip
Play 5.0.6 Link is: http://software.soundsonline.com/Products/PLAY/Play_5.0.6_Win.zip
Play 5.0.1 Link is: http://software.soundsonline.com/Products/PLAY/Play_5.0.1_Mac.zip
Play 5.0.6 Link is: http://software.soundsonline.com/Products/PLAY/Play_5.0.6_Mac.zip
To use, unintall Play 6 first. Play 5 and Play 6 keep their user files in different locations, and they don’t get wiped when using the installers to roll back and forth. So, swapping around is easy enough. Unintall the current one with your OS installer manager, run the installer for the one you want to use.
You can leave Opus alone. No need to uninstall it or anything. I’ve not had much luck using it (VST3 nor VST2) directly in Dorico. Word builder doesn’t work at all, and other issues pop up (sticky notes for one, they never stop playing)…ESPECIALLY when trying to export to audio…