macOS High Sierra has just been released and I can confirm the app works fine with it, so that’s great!
Just when running for the first time on a machine and with macOS High Sierra, users will need to aprove the kernel extension manually by clicking “allow” on System & Security settings under control panel after trying to disable turbo boost also for first time only (thanks, Apple).
The first time this happens (and just the first time!) Apple will display also an user Alert like the following one to remind the user he/she needs to allow the kext to be installed like described above.
If you upgraded your macOS from a previous version with the app already installed, this won’t be neccesary.
If you don’t do that, turbo boost won’t be disabled since Apple won’t allow the kernel extension to be used.
In summary, and only for first runs on a machine with also macOS High Sierra:
- Set manual mode and click on Disable Turbo Boost option.
- After some seconds, and if turbo boost is not disabled, go to security settings and you’ll see a screen like the above one.
- Click on allow.
- Click again on disable turbo boost…, done! You’ll never have to do this again…, according Apple documentation ;).
Sorry for the inconvenience, but this has nothing to do with the app (in fact, affects all apps that include a kernel extension). This is due to a new “feature?” introduced by Apple on High Sierra that forces users to manually aprove any app that uses kernel extension, no matter if it’s signed or not or which company it comes from.
Here you’ve got more explaining the process: https://developer.apple.com/library/content/technotes/tn2459/_index.html