Help installing Mac OS on an iMac Late 2009

[ron963]

Hi,

 

I recently acquired a late 2009 iMac from someone who upgraded to a newer iMac and wanted to get rid of the old one. I'm new to Mac's and need some help installing either Sierra or El Capitan. The system was wiped when I received it and I'm having a hard time installing the OS. Here's what I've tried:

 

- Erased the HD as journal/GUID

 

- Over the network El Capitan installation doesn't work as it says "This item is temporarily unavailable. Please try again later."

     - I tried the fix available here and it doesn't work.

 

- Downloaded Sierra using another compatible Mac and made a bootable SSD drive - when I boot from the drive it just shows a circle with a line. I used the following instructions for that.

 

- Made OS X Recovery Disk Assistant v1.0 -  booted to Disk Utility and did the manual restore of Sierra and I still got the circle with line when I boot up. 

 

- Manually restored El Capitan - this time it booted into the installation process, however, first I got this message; "This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading."

     - I followed the date method to fix the error here.

     - Now I get the following message "The installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance....Restart"

     - I again erased the drive and redid the restore process and now I can't get past that error message at all. 

 

I need some Mac expert help to install the OS. I understand this is an old system, however, I'd like to keep a running Mac to get experience and learn the OS. 

 

Thanks!

 

[allannyholm]

The best thing you can do is skip what ever the easiest method might seem to be for creating an USB installer for macOS Sierra or El Capitan. Use the Terminal commands instead on the page you link to. Copy and paste to TextEdit and replace the /Volumes/***** with your own USB drive name

 

The USB should be formatted to a GUID + Extended Journaled. At least a GUID partition table - the formatting will be taken care of by using the Terminal command.

 

You can add --nointeraction as a setting at the end of the string to skip any interaction when making the USB drive containing macOS Sierra.

 

Btw. When formatting and applying a partition table on the drive; take the top most available drive name named APPLEHDD or similar - not the Macintosh HD name.

 

I can't see why there would be any sign not allowing you to install on that disk -  There must be something wrong with the formatting on that drive despite the correct partitiontabe of GUID and Extended Journaled filesystem.

 

Can you check the drives for errors after booting from the USB install of macOS Sierra using the Disk Utility program within?

 

And if you're sure that it is a Late 2009 iMac then macOS Sierra should be allowed to install given that drives are formatted correctly.

 

(NOT USED IN ALL CASES AND RARELY DOES MUCH. THE SMC RESET CAN HELP WITH SHUTDOWN ISSUES AND SLEEP ISSUES)

There shouldn't be need for any tricks. Only things I can thing of is that you can reset the SMC on the iMac and possibly reset the PRAM also using CMD+OPTION+P+R after the initial chime and then let got after hearing the chime a second time(Shhould be a very loud chime because the volume of the chime is stored in NVRAM (AFAIK) and is forgotten until it settles)

Edited October 12, 2016 by allan.nyholm

[protocol7]

Sierra dropped support for a number of older Macs. It might not be compatible with your "new" iMac.

 

As for El Capitan, making a bootable USB is the easiest way. Or you could try and make a bootable SSD like you did with Sierra.

[allannyholm]

Apple has this page - just make sure the iMac is a late 2009 iMac and it should allow installation of macOS Sierra

 

https://support.apple.com/en-us/HT201475

[ron963]

Sorry for a super late response. I was able to figure out the installation and I made a couple of mistakes:

 

1. I took the word of the person who gave me the iMac thinking that it was Late 2009. It is actually a mid 2007 iMac, therefore, Sierra is out of the question.

2. I wasn't deploying El Capitan correctly. I was restoring the dmg to the primary HD and running the installation from there. I was able to install the OS when I restored the dmg to an external driver and booted from that drive to start the installation process. 

 

Thanks for all of you replies. Now I can learn Mac OS and not make simple mistakes  .

[allannyholm]

Did you obtain your El Capitan .dmg from a reputable source? A torrent doesn't make a good starting point if you chose that route.

 

But if everything is in order then don't worry. Just scan your install of El Capitan with the Anti-malware tool for Mac from https://www.malwarebytes.com/antimalware/mac/