iMac 27-Inch "Core i7" 3.4 (Mid-2011) trying to install MacOS

[Vin76]

Hello to all forum members

Info:
iMac 27-Inch "Core i7" 3.4 (Mid-2011) <--[Target]
3.4 GHz Core i7 (I7-2600)
Previous MacOS installed - Unknown
Currently installed system - Win 10 x64
I do not have another apple computer with MacOS to try to prepare the installation disk on it, using, the built-in apple programs.

Problem:
I have a problem with reinstalling the MacOS system - the computer does not detect a prepared bootable USB flash drive.

What has been done:
1.Multiple attempts to prepare a pendrive with the High Sierra system from a legal source (AppStore)
2.Flash drive prepared both with the 'diskpart' tool (clean, convert gpt, create partition primary etc.) and a with 'TransMac' program. (On another Win10 system)
3.Various key combinations at boot, (Reseting PRAM, repluging device meanwhile starting system, etc.)

Result:
iMac still does not detect the system on the pendrive, during start-up.

**there is always only one option 'EFI boot only'...
Please help

 

[Fishrrman]

You need to put together a USB flash drive that works.

I suggest you download and use one of these small, free utilities:
- DiskMaker X
or
- Install Disk Creator

Either one should do the job.

Another alternative:
Have you tried INTERNET recovery?
Command-OPTION-R
at boot.

or...
A special version of internet recovery that installs the version of the Mac OS that the iMac shipped with:
Command-SHIFT-OPTION-R
at boot.

 

[rpmurray]

Insert the Snow Leopard (10.6.x) disk that came with it when you bought it and boot from that.

 

[DeltaMac]

The challenge is making a bootable Mac installer on Windows that will actually work.
I think that your "life signs" need to be all lined up perfectly (with some luck involved), before you will be successful in using Windows to create a bootable USB installer that will successfully boot a Mac.

If all else fails, you can purchase bootable USB macOS installers on Amazon or eBay, etc.

 

[Nguyen Duc Hieu]

I believe the Internet Recovery mode can be used for this iMac 2011, can't it?

 

[DeltaMac]

I believe the Internet Recovery mode can be used for this iMac 2011, can't it?

Yes, Internet Recovery should work, too.

 

[Vin76]

You need to put together a USB flash drive that works.

I suggest you download and use one of these small, free utilities:
- DiskMaker X
or
- Install Disk Creator

Either one should do the job.

Another alternative:
Have you tried INTERNET recovery?
Command-OPTION-R
at boot.

or...
A special version of internet recovery that installs the version of the Mac OS that the iMac shipped with:
Command-SHIFT-OPTION-R
at boot.

I dont have any working computer with MacOS to use this programs
Internet recovery is available but -


I talked to a friend who previously tried to reinstall the system on this iMac and I got this info:
All attempts to reinstall MacOS ended with a crash after more than 50% of the installation ('somewhere at the end')
The previous (instaled) MacOS system crashed.
One option that worked till now was to install Windows 10.

But:

after recent tests with Crystal Disks and HD Tune:
1. The temperature on the disk is almost 60 degrees Celsius (55,56,57,58,59)
-> after ~~15 -30 min from powering on - computer gets very hot - is this normal? (even with total afk)
2. Bad sector was found.

and now the question is - whether this could be the cause of the system installation failure?


If I need to replace the disk:

Can I 'just' replace the disk with any matching one or there will be any problems if there is no 'Mac - disk'?

Insert the Snow Leopard (10.6.x) disk that came with it when you bought it and boot from that.

I do not have the original disc that come with this iMac.



**Thanks for all the answers so far **

EDIT: added some screenshots from HD Tune and Cristal Disk (Fresh Start/Power ON)

 

[Nguyen Duc Hieu]

All your troubles came from a bad HDD. After nearly 10 years of service, it's at the end of its life.

I would suggest you just replace it with a 2.5" SSD and try Internet Recovery again. Any SSD will do.

The HDD fan will run like crazy at first. You can use Mac Fan Control app to slower it down.

 

[rpmurray]

If the iMac is getting really hot it's either a failing hard drive or the fans aren't working. Do you hear the fans going (it has three)? Considering how old this iMac is, if it hasn't been serviced during that time then the fans could be clogged with dust or other detritus.

Replacing the hard drive with an SSD would not only cool things down but also make the iMac speedier (after cleaning the fans).