IMac 24 inch El Capitan

[Desh]

Hello
I have a blank white screen on the iMac. I acquired it from a friend, fully functional. I Formatted it so I had a fresh start.
I tried to reinstall El Capitan but got a error message ~ software version corrupted. Bought a flash drive with OS to hopefully do a reinstall.
Same white screen.
Any help gratefully received.
Thanks.

 

[Rodananne]

The Flash Drive may have a macOS installer on it but not be bootable.
To test this turn the Mac off, plug in the Flash drive, Startup while holding down the Option Key. You should see any bootable source displayed. If the Flash Drive is bootable it will appear as an option. If it appears click on it and you should (eventually) see a screen with options, one should be Instal macOS.

You should also see Disk Utility. If so I would suggest you use this app first to erase the internal drive at the "media" level. That means the manufacturer's name of the HD, top of the list in the side bar when show all Disks is selected. Click on erase then you will need to name it = Macintosh HD, format it = MacOS Extended (Journalled) and map it as GUID.

If not you will need to buy a "Bootable macOS installer for El Capitan" on a USB Flash Drive which are readily available on eg. Amazon. Then follow the above directions.

Erasing it will ensure there are no conflicting leftovers from the previous user.

 

[Desh]

Hello Rodanne,
Thankyou for your reply.
When I press the on/off button on the machine, I hear a whirring like something attempting to start but not quite making it. Then I get the chime, then a blank white screen.

 

[Rodananne]

This is while holding the option key down?
At least you get the chime, that's a good sign. The whirring may be your HDD spinning up, that's normal for mechanical hard drives.

 

[Desh]

Yes when holding down the option key.

 

[Rodananne]

Sadly that doesnt really tell us much. The USB may be defective or not bootable or the computer unable to see it. Without a known and tested bootable USB we cant really say.
Have you tried booting into Recovery? Try switching the device off, disconnect the power, leave for a few minutes then startup holding the R key or in some cases the Command + R key. It varies a little depending on model.
If you get the Restore Partition you can reinstall macOS from there.

 

[Desh]

Hello
the same result. The chime, then a blank screen
thanks

 

[Rodananne]

That would seem to indicate that your Hard Drive (HD) has completely died.
This leaves you with one of two alternatives, short of buying a new Mac. You can take it to a reputable repairer to install a new HD complete with an suitable Operating System or if you have access to another Mac you could create a bootable drive on an SSD USB External Hard Drive.
I suggest a SSD (Solid State Drive) because the old spinner drives (HDD's) are not fast enough for the task.

It's actually a fairly simple process in principal. Download the macOS installer for El Capitan on another Intel Mac and use it to instal the Operating System onto an External Drive. Plug that drive into your iMac and select it as the boot volume on startup.
If you are really lucky it may even recognise your old internal Macintosh HD and allow you to copy some of your files.

 

[Desh]

Thanks.
I’ve stripped the iMac down and have ordered a replacement HDD.
I also have the Flash drive I mentioned early. A boot/restore USB drive with El Capitan on it.
Once I’ve rebuilt the machine should it boot from the the flash drive or is it more complicated than that.
thanks
Des

 

[Rodananne]

If the flash drive is connected on booting yes, in theory the Mac should boot from the flash drive.
After getting over that hump you can take a deep breath and congratulate yourself.
From there you can either run the installer on the flash drive, effectively turning it into your Start Up Disk or Install El Capitan onto the new HDD.
Don't forget that running the installer erases it. So if you think you might need it again copy it elsewhere.

 

[Desh]

If the flash drive is connected on booting yes, in theory the Mac should boot from the flash drive.
After getting over that hump you can take a deep breath and congratulate yourself.
From there you can either run the installer on the flash drive, effectively turning it into your Start Up Disk or Install El Capitan onto the new HDD.
Don't forget that running the installer erases it. So if you think you might need it again copy it elsewhere.

Ah . OK. Thanks very much, I’ll keep you posted

 

[Desh]

New HDD installed. I formatted it first and copied the El Capitan installer onto it. Also had the flash drive plugged in.
Same problem. No change. Hmm?
The chime,same attempted whirring, blank white screen.

 

[MacsBug]

Do you have access to another Mac so that you can make a bootable installer?

 

[Desh]

I have an iMac G4 and an external HDD. I used this to format the disk and also copied the El Capitan installer ont it.
So yes, if that’s adequate.
thanks

 

[MacsBug]

If you now someone that has an intel Mac then you can have them download DiskMaker X (diskmakerx.com) and then they can make you a bootable installer for El Capitan that you can use to install the OS on your Mac.