Hello Wim,
Way back in August or so my windows natural voices croaked also. At the time I merely moved back to the horrible "default" voices, without deleting the natural voices. At length, I couldn't stand them any longer and looked for ways to restore the naturals. Though there have been many methods addressing the issue, I didn't have much success, not being a computer geek.I am using Windows 10, FS9 and this is how I was able to restore the beloved natural voices.....
- first I installed the latest updates for P2atcv3 https://www.pilot2atc.com/index.php/v3-updates : P2ATCv3 EarlyAcess 0.2.9 and P2ATCv3 EarlyAcess 0.2.8
- next I installed the latest Sapi adapter, available here: https://github.com/gexgd0419/NaturalVoiceSAPIAdapter/releases NaturalVoiceSAPIAdapter_v0.2.9_x86_x64.zip
To check your work, without needing P2atc going, go to: c:windows\system32\speech\speechux , the file you are looking for is sapi.cpl and click on the text to speech tab. If the voices are working here, they will be working in P2atc v3, This is how I was able to restore the undeleted natural voices to functionality which I had been using previously, I think once you get Windows to recognize the natural voices once more, you should be able to install others using the conventional installation methods. You did not specify which Windows version you were using, and you seemed to have complicated your original problem in attempts to rectify the issue, however, I hope this will be of some help.