Cannot Add OnyX

OS High Sierra > Macbook Pro

A student has downloaded OnyX, everything kosher, but cannot open the utility because of something in Security & Privacy. Trying to add OnyX to the recognised applications cannot happen because there are no + or - buttons available. Oddly, another student with an older Macbook, but also running OS H-Sierra was able to add OnyX via displayed +- buttons. Are we missing something? Enlightenment please.

Right Click the Onyx icon mate and see if that gives the 'open' option. Gatekeeper ensuring safety first from Mother Ship .

In Security & Privacy, under the General tab, there should be an "Allow/Install" button, unless the pop-up window was closed.

Bob and Harry have given you the answer, but I'll repeat it. Gatekeeper is a function in macOS that blocks installation of software not from authorized developers registered with Apple. However, you can still install by right clicking on Onyx and click on the Open button in the resulting warning. The warning is that OnyX is not from an authorized developer (by Apple's thinking) and can be ignored. Once installed, you won't have to go through that again, as the Gatekeeper will have "learned" that you trust OnyX.

You may have to right click on the OnyX icon in the Applications Folder. Assuming you have finished the installation.

Rather a long shot and almost certainly something you've excluded; OnyX is OS version specific.

So OnyX for Sierra will not install or work on a Mac running High Sierra.

Ian

Thanks to all, will try those options when I next meet the students. The OnyX version was the correct one, double-checked that, but I didn't know Gatekeeper was part of H-Sierra. If it's of interest, Joël Barrière, the developer of OnyX, told me that Apple had included some of the Permissions and Script maintenance in its latest OS.

Some of the features of Onyx have indeed been part of the OS for quite some time. The nice thing about Onyx is that it consolidates these scripts into one convenient package. Many of the scripts run automatically but, in the past, some of these scripts have needed to be run as Terminal commands. That's generally not necessary using Onyx.