![Onyx mac os x 10.9.5 Onyx mac os x 10.9.5](https://screenshots.macupdate.com/JPG/11582/11582_1545655850_scr_uc4.jpg)
G'day and welcome to the forums. Well Doc, you are still chasing me age wise young fellow! Suggest you download Onyx for your operating system, Mavericks, from the link below and don't worry too much about it. What is more important is how much free space your iMac enjoys on the hard drive and how much memory is installed. Just click on the link for Mavericks OS X.9. Onyx is free and the best cleaning system for our Macs, and avoid Mackeeper and other cleaning utilities and I personally will not have antivirus software on my iMac as there are no Mac OS X viruses.
Nov 14, 2012 - Download Onyx for Mac, the #1 utility to repair permissions, clear cache, and speed up. Download OnyX 2.8.8 for Mac OS X 10.9 Mavericks. Onyx Mac – Instant Download Onyx for Mac OS X Onyx Mac. OnyX Mac OS X System Maintenance. OnyX mac is an all-in-one system maintenance tool and optimizer. It is a very simple and light application that comes with a variety of maintenance tools that can be run to make sure that you are enjoying your system at its fullest.
First if your computer is running slow a bit more information would help. How full is your hard drive? Click on the apple icon in the upper left corner of your screen and select About this Mac.
On the screen that opens up click on the storage button and tell us how large is your hard drive and how much of your hard drive is free. I suggest you download a utility called and run it. Be sure to pick the version that works with your version of OS X. It will do a lot of cleaning out of stuff you do not need and it is very safe. It is free and once installed it will run a check on your hard drive and then open up the interface.
Run the Automation mode and restart your mac. IF your hard drive fails the SMART check that Onyx runs on startup you will need to open Disk Utility and run disk repair and permissions repair then run Onyx. Post back results and any more information you have. Your friend's idea of cleaning out files will only help to free up disk space - which could be part of the issue if your drive is really full. But I think Onyx will help more as it clears built up cache files and more.exe are indeed windows files and won't run on your imac. Not sure how they got there even.dmg not really needed as you can in most cases download them again when needed.wmv may have Windows in their name but these are video files and will run on your iMac. Only you can know whether you want to keep them.
![Onyx for mac os x yosemite Onyx for mac os x yosemite](http://i1-mac.softpedia-static.com/screenshots/18-1703_1.png)
Why not play them and then decide. To find them click on the Spotlight icon (the magnifying glass) at the top right hand side of your screen and type 'exe' or whatever.
Once done you don't need to 'clean them out' every few months and they don't just get there by accident. Just run Onyx as suggested every so often and you'll be fine.