First, always update your system and the applications found here.
If you have a problem with one of these applications, you can find an answer in the help. (In the application, choose the Help menu.)
If you have another problem, contact me via email by clicking Contact in the navigation bar at the top of the pages, or from the application (for example, OnyX menu > Provide OnyX Feedback).
Please, report the problems with the latest final version for macOS High Sierra only (not with the beta versions).
The development of the old versions is discontinued, and the applications will be not updated anymore.
Quickly find answers to your common questions. If you need help solving a problem you're having, you can find solutions here.
Here are all of the known problems and bugs reported by users.
Here are links to documents on the Apple support site and miscellaneous news sites for quick access to some useful technical information.