Reinstall OS X El Capitan

[PossumNZ]

My computer is a 2009 iMac running El Capitan version 10.11.5.

I would like to do a reinstall of El Capitan but since having done software upgrades it is not same as when I was running Snow Leopard on this iMac if a reinstall of the OS was needed.

I have tired restarting the iMac and holding down the Command key + R after hearing the startup chord, to click and start the Reinstall OS option, but the computer the OS starts as normal.

Also noticed when clicking on Utilities then "Disk Utility" the window is far different to Snow Leopard's Disk Utility window, which had the options to start the reinstall.

My iMac doesn't seem to running as quickly and efficiently just recently. Also other out of the ordinary issues lately have me wondering if I may have a malware problem in the OS.

I would appreciate if other Mac users can advise me how do a reinstall of El Capitan OS.

 

[honestone]

OK, we first need to know some more information:

1. How much free space is on your internal drive?

2. Are you making backups to an external device? Time Machine is OK, but a backup/cloning program like SuperDuper! or Carbon Copy Cloner is better.

3. Have you done any disk cleanup/repairs/maintenance at all? If you use Disk Utility for that, to do a complete job, you would need to do that "externally". That is where a bootable backup made via SuperDuper! or Carbon Copy Cloner is excellent for that. (If you have a more robust Disk maintenance/repair program like TechTool Pro or Disk Warrior, that is even better (still along with the backup)).

4. Not sure if you need to repair permissions. That feature, alas, is no longer available in the version of Disk Utility that comes with El Capitan. However, there is an excellent, stable, well reviewed freeware program entitled Onyx that still has that feature (and works!), along with other useful tasks. You can get it form here:

http://www.titanium.free.fr/onyx.html

Make sure you get the first one, version 3.1.7, on that list, as you are using El Capitan.

5. Do you have the file "Install OS X El Capitan" some where, either in your Applications folder and/or somewhere else? Also, assuming you have that file, not sure which version of OS 10.11 it is. So, let us know how you "arrived" at the latest version of El Capitan, OS 10.11.5.

6. There is an excellent freeware program called Malwarebytes Anti-Malware that can help with "malware" issues. You can get it from here:

https://www.malwarebytes.com/antimalware/mac/

After you download it, install it, and then run it.

7. Do you have either MacKeeper and/pr CleanMyMac installed? If you do, get rid of them IMMEDIATELY, as they cause much more harm than good.

8. Do you have another Mac? If you do, there is a possibility that it can be used to re-install OS 10.11.x on your iMac. But, you'll still need a backup.

I'm not sure why Command-R is not working. I myself have TechTool Pro, and thus don't really need the (hidden) Recovery HD partition (which is where your machine would boot from via the Command-R combination).

 

[PossumNZ]

Sorry a bit late replying to your helpful post "honestone" which I printed out for followup and reference.

I have successfully completed the reinstall of El Capitan on my iMac, all completed and Apps reinstalledin close to 3 hours.

Firstly I completed a full backup of El Capitan OS to a Seagate 1TB external hard drive. Also for extra security I copied all special downloaded Apps setups installed, Documents and photos to save to the external hard drive.

To open the "Disc Utilities Window" I needed to shut my iMac completely down, then keep holding down the "Command + R keys" when turning on the iMac and finally the "Disc Utilities Window" opened.

No problems with the reinstall other than the time taken reinstalling any downloaded Apps. Also downloaded the Malwarebytes Anti-malware programme.

I have don't have MacKeeper or CleanMy Mac installed and thanks I will not anytime soon.

The reinstall has given a fresh look to my iMac which appears to be running a lot more quicker.

Although I think a future issue could be a replacement of the 4 year old hard drive, judging by the occasional "coloured ball" spinning when opening some programmes.

I must keep my backups up to date in case of a computer crash in the near future.

Once again many thanks for your advice.