Can't reinstall MacOS

[Finite1]

I'm new to Macs and Apple. I've a iMac 2009 which was given me. Installed by default was Mavericks which was upgraded to Catalina successfully. I then installed OCLP. This was a success. I then installed Sequoia using OCLP successfully following guides. I was able to go into recovery mode. I then tried to install Windows 11 on a partition that I created using Utility Disk. This was unsuccessful as I did not originally partition the drive in an MBR format and no matter I've formatted the Windows partition to exFat, Windows would not install.

Anyway, I then tried to install Sonoma using the created boot disk using OCLP. This went all the way to the settings page where you put location etc. I did ask OCLP to create another partition (200MB) to install OCLP again (it's now clear this wasn't required as this was already done when I installed Sequoia). I removed the USB disk for Sonoma and hard powered off the iMac. I then tried to install Windows 11 via DVD disc. Again this was unsuccessful as the format wasn't correct.

I used a software (I forget what it's called) to convert the entire hard drive from the file structure MacOS created to exFat (I think) in Sequoia using terminal following the guidance.

MacOS will no longer boot. I cannot get into recovery mode. I have tried several things to do so including command +r, command +alt +r, cmd+alt+r+p, unplugged the iMac for 15 seconds and then plugged in and let 5 seconds run etc. and nothing works.

I have attempted, repeatedly, to boot from either the Sequoia or Sonoma USB bootable flash drive, selecting alt and the choosing the MacOS (not at the same time, the USBs are not attached to the USB ports at the same time ). I choose the EFI MacOS (Sequoia, say), it runs for a while and then I get an error message with 2 screens (which alternate) stating "support.apple.com/macsetup". I don't know what the 2 screens error messages mean.

At boot up (when I press Alt) I get the option to choose: Install Sequoia (which runs for a bit but error message occurs, as above, the USB bootable disk is attached to the USB port) or Windows installation (via DVD) as I cannot remove the disc from the drive as there is no O/S for me to do this. When I try to install Windows I can go all the way to settings but the partition structure is not recognised so it will not install.

Can I install MacOS to USB and to run via USB drive and then try to get into the recovery?

I attach the photos with the errors.

Please advise what I can do to get either MacOS running. Thanks


UPDATE: After spending many hours and days I deleted all the partitions using the Windows installation disc and was now able to install Windows. I have tried to install Sonoma using the bootable disk, it runs for a short while and stops with the error messages as discussed above. I cannot seem to install MacOS anymore.

 

[!!!]

You'll presumably need a USB installer of a supported version of macOS. Boot off that and reformat your drive correctly, then reinstall.

From there you can mess around with OCLP and whatnot, but I'd recommend installing Windows via the Boot Camp assistant. Don't try to mess with the partitions yourself.

 

[mreg376]

Once you go down the OCLP road, your particular computer is in uncharted territory.

 

[Ruggy]

Did you post this before a while ago?
OK, you can only install the version of Mac Os that came with the computer hardware when it was launched and then you can upgrade. This is to do with the bios. That means you probably need to install Snow Leopard first and then upgrade from there. You probably need original installation disks for that as I don't think it was available on USB drive and so Ebay would be your best bet and you need the ones with a picture not the grey upgrade ones - which won't work for a fresh install
If it was Snow Leopard that won't work with Exfat.
I'm very surprised you managed to get Windows to work without a version of Mac Os. I didn't know it had any drivers that worked with the Mac. It's an entirely different system it isn't just a case of a different OS. The Mac Kernel is on a chip. I don't think Windows has access to that without Mac OS being present.
I don't think it will be able to control fans or anything like that either as they are on a hidden partition on the HD and if you've formatted that then you've maybe lost them (maybe not).

 

[iStorm]

I choose the EFI MacOS (Sequoia, say), it runs for a while and then I get an error message with 2 screens (which alternate) stating "support.apple.com/macsetup". I don't know what the 2 screens error messages mean.

These two screens are telling you to turn on the Magic Keyboard and Magic Mouse, meaning the installer isn't detecting any keyboards or mice connected to the Mac.

Not sure what keyboard and mouse you're using, but this is likely due to Ventura removing support for USB 1.1 drivers. There's a note about this linked on OCLP's site, and a workaround provided (use a USB 2.0 hub to plug your keyboard and mouse into).

Legacy UHCI/OHCI support in Ventura and newer · Issue #1021 · dortania/OpenCore-Legacy-Patcher

In macOS Ventura, Apple removed support for all USB 1.1 drivers leaving some older Macs unable to use USB 1.1 peripherals. The main drivers removed where those of UHCI and OHCI controllers: AppleUS...

github.com

OK, you can only install the version of Mac Os that came with the computer hardware when it was launched and then you can upgrade. This is to do with the bios. That means you probably need to install Snow Leopard first and then upgrade from there.

I've never heard of this before. As far as I know, we've always been able to clean install any version the Mac supports. I've been able to do clean installs of the latest macOS version without having to install the version it shipped with first.

Of course when you use OCLP, then things can get a little hairy...

 

[Finite1]

Did you post this before a while ago?
OK, you can only install the version of Mac Os that came with the computer hardware when it was launched and then you can upgrade. This is to do with the bios. That means you probably need to install Snow Leopard first and then upgrade from there. You probably need original installation disks for that as I don't think it was available on USB drive and so Ebay would be your best bet and you need the ones with a picture not the grey upgrade ones - which won't work for a fresh install
If it was Snow Leopard that won't work with Exfat.
I'm very surprised you managed to get Windows to work without a version of Mac Os. I didn't know it had any drivers that worked with the Mac. It's an entirely different system it isn't just a case of a different OS. The Mac Kernel is on a chip. I don't think Windows has access to that without Mac OS being present.
I don't think it will be able to control fans or anything like that either as they are on a hidden partition on the HD and if you've formatted that then you've maybe lost them (maybe not).

No, this was my first post. Thank you for your advice.

 

[Finite1]

These two screens are telling you to turn on the Magic Keyboard and Magic Mouse, meaning the installer isn't detecting any keyboards or mice connected to the Mac.

Not sure what keyboard and mouse you're using, but this is likely due to Ventura removing support for USB 1.1 drivers. There's a note about this linked on OCLP's site, and a workaround provided (use a USB 2.0 hub to plug your keyboard and mouse into).

Legacy UHCI/OHCI support in Ventura and newer · Issue #1021 · dortania/OpenCore-Legacy-Patcher

In macOS Ventura, Apple removed support for all USB 1.1 drivers leaving some older Macs unable to use USB 1.1 peripherals. The main drivers removed where those of UHCI and OHCI controllers: AppleUS...

github.com

I've never heard of this before. As far as I know, we've always been able to clean install any version the Mac supports. I've been able to do clean installs of the latest macOS version without having to install the version it shipped with first.

Of course when you use OCLP, then things can get a little hairy...

Thank you for your reply. Using a Windows keyboard and and blutooth mouse. Will get the original keyboard and mouse shortly. Maybe this explains it.

 

[Finite1]

Notwithstanding what's been said above (and prior to reading them), I managed to get the iso and dmg file for MacOS Leopard 10.5.4. I think it came with Leopard 10.5 (as per Apple). I have burnt the iso to disc/DVD. I tried to install the DVD (recognised as an install disc), runs for a bit and get the error message "support.apple.com/mac/startup". Do I need 10.5 or is 10.5.4. fine? I will also wait till I get Apple keyboard and mouse. I didn't think it would make a difference if I used a Windows and non Apple (blutooth) mouse so long I was using the appropriate keys.

 

[haralds]

You'll presumably need a USB installer of a supported version of macOS. Boot off that and reformat your drive correctly, then reinstall.

From there you can mess around with OCLP and whatnot, but I'd recommend installing Windows via the Boot Camp assistant. Don't try to mess with the partitions yourself.

Also, always keep a (small) partition or volume of the last natively supported version of macOS. It will make recovery and repair a LOT EASIER!!!

 

[Ruggy]

These two screens are telling you to turn on the Magic Keyboard and Magic Mouse, meaning the installer isn't detecting any keyboards or mice connected to the Mac.

Not sure what keyboard and mouse you're using, but this is likely due to Ventura removing support for USB 1.1 drivers. There's a note about this linked on OCLP's site, and a workaround provided (use a USB 2.0 hub to plug your keyboard and mouse into).

Legacy UHCI/OHCI support in Ventura and newer · Issue #1021 · dortania/OpenCore-Legacy-Patcher

In macOS Ventura, Apple removed support for all USB 1.1 drivers leaving some older Macs unable to use USB 1.1 peripherals. The main drivers removed where those of UHCI and OHCI controllers: AppleUS...

github.com

I've never heard of this before. As far as I know, we've always been able to clean install any version the Mac supports. I've been able to do clean installs of the latest macOS version without having to install the version it shipped with first.

Of course when you use OCLP, then things can get a little hairy...

 

[n-evo]

OK, you can only install the version of Mac Os that came with the computer hardware when it was launched and then you can upgrade. This is to do with the bios.

A) First of all; that’s nonsense. I’ve been doing clean installs of whatever most recent Mac OS X/OS X/macOS version a Mac supports since forever. Back in the PPC and Intel days, and now with Apple Silicon Macs. Hell, you could boot a Mac OS 8 iMac G3 straight to Mac OS 9 if it didn’t have anything on the HDD.

B) Intel Macs don’t have bios, they utilize EFI.

@OP Have you tried installing the latest officially supported macOS version first? I think that’s macOS High Sierra in your case. I’d go that route and then try to “hack” yourself using whatever tools to get a later macOS version to install.