OnyX and slow iMac

[pilgrim1936]

I am running OSX 10.8.4 on my iMac. It has recently started running very slowly. Elsewhere I saw a recommendation to install OnyX. I downloaded it, but when I tried to install it, I received a message to the effect that this was not downloaded from the App Store and so my settings did not permit me to install it.
Any suggestions as to whether it is worth installing OnyX - I realise that some say yes and some say no - and, if yes, how to get around the settings not allowing the installation.
Also, any other suggestions please as to how to rejuvenate my iMac without formatting the hard disc and reinstalling the software from scratch?

 

[IWT]

This is quite in order. Apple adds an additional layer of security which simply advises you that you are downloading an app outside of the Apple App Store.

OnyX is a great app and secure.

So, go into System Preferences>Security & Privacy>General. Then check the box: "allow apps from anywhere"

Now OnyX will run fine. Afterwards, it will continue to run, but if you are very security-concerned, you can always return to the Security & Privacy settings and re-check the "only allow from app store" if that's what you want.

Ian

 

[pigoo3]

Any suggestions as to whether it is worth installing OnyX - I realise that some say yes and some say no...

The overwhelming majority say "yes"...I'm not sure I can remember the last time I read someone familiar with Onyx say "no".

So it's clearing not an "on the fence"...50/50...sort of decision.

- Nick