In over my head....

[squash junkie]

So I removed the mac OS and installed ubuntu 18.04 on my imac....and am completely over my head.
I cant seem to boot into any recovery mode for the Mac OS, and cant get the ubuntu OS to recognize the USB with a bootable image on it at startup.
I cant seem to find a post to restore the iMac to a state where I can reinstall the Mac OS...and seem stuck with this Ubuntu OS.
Does anyone know of any step by step guide, or knows what I can do, to get rid of this ubuntu install and return to OS X?

like I said, i'm in over my head with linux...

 

[294307]

Well that was a stupid thing to do, wasn't it?

Try starting up from Internet Recovery holding down Shift (⇧) - Option (⌥) - Command (⌘) - R when you start up your Mac. If that doesn't work, you will need to get a copy of macOS onto a pen drive to reinstall the operating system. You'll need another Mac in order to do this. If you have another Mac to use, download macOS from the Mac App Store and follow the instructions in this Apple Support article to create a bootable macOS installer. Once you've got macOS ready on a pen drive, start up your Mac and hold down the Option (⌥) key to enter the boot menu. You should see two drives listed – using the arrow keys on your keyboard, select the pen drive you put macOS on and press Enter to boot into the macOS installer.

When the macOS installer boots, you'll need to erase the drive so it is prepared for macOS. In the macOS installer, go to Utilities > Disk Utility from the menu and select your computer's built-in drive from the left-side and erase it. Make sure you select Mac OS Extended (Journaled) as the format. The installer will automatically convert the drive to the APFS format if it needs to. Please note by erasing the drive you'll lose all the data currently on it.

If you have a Time Machine backup, plug in the hard drive before you begin reinstalling macOS. You'll be given the option to restore from this backup when you go through the macOS install process. If you don't have a Time Machine backup, then I'm afraid you've lost all your data.

If you don't have another Mac to create a bootable macOS installer, you'll need to go to an Apple Store and explain the situation to them (I would recommend making a Genius Bar reservation). They should have bootable macOS installers for the Genius Bar engineers to use who will be able to reinstall macOS for you. They may charge you for this service but they will advise you of that before they help you. If you don't have an Apple Store nearby, you'll need to go to a local Apple Authorised Service Provider instead.

 

[squash junkie]

yes particularly stoopid....so I'll take that one on the chin.

Ive tried the internet recovery, it seems to connect to the wifi, but then no status bar downloading....just the globe spinning. So not sure if its going anywhere...

actually just given me an error....so thats a no go....

 

[Kes.Siebring]

You can download macOS iso & create bootable USB under the Ubuntu.

 

[294307]

yes particularly stoopid....so I'll take that one on the chin.

Ive tried the internet recovery, it seems to connect to the wifi, but then no status bar downloading....just the globe spinning. So not sure if its going anywhere...

actually just given me an error....so thats a no go....

If it didn't take long before the error appeared, try connecting via Ethernet and try Internet Recovery again. If not, you'll need to create a bootable macOS installer and you'll need access to another Mac to do that.

Can you remember what model your iMac is? For example my iMac is a "Retina 5K, 2017". Some older Macs can't be upgraded to the most recent version of macOS, which is Mojave. And this is the only version readily available in the Mac App Store. We'll be able to confirm exactly what version of macOS you can install and how you can download it if you tell us what model your iMac is or at least how long you've had it for and whether you bought it new.

If you already know you need to download an older version of macOS, you can follow the instructions at the end of this Apple Support article which provides download links for OS X El Capitan, macOS Sierra and macOS High Sierra that will automatically open the Mac App Store for you. This is the only way to download older versions of macOS as they are hidden in the Mac App Store by default. Again, you'll need access to another Mac in order to do this.

Once the macOS installer is downloaded, it may automatically open. Just quit the installer using Command (⌘) - Q and then follow the instructions in this Apple Support article to create a bootable installer from it. Again, you'll need a spare pen drive available. When you copy the macOS installer onto your pen drive, be aware the pen drive will be permanently erased to make room for the installer.

 

[squash junkie]

So, finally sorted it, thx.
Made a bootable usb disk using TransMac and High Sierrra dmg image. Booted into this usb stick by holding the ALT key on a windows keyboard plugged into the iMac (wireless bluetooth mac keyboard wasnt responding) and formatted the disc accordingly.
Installed High Sierra and back to normal....
Thx again for all your help... next time i wont try and be such a smart ass

 

[wardie]

Maybe use virtualisation software to run Linux from “within” macOS?

 

[alien3dx]

So, finally sorted it, thx.
Made a bootable usb disk using TransMac and High Sierrra dmg image. Booted into this usb stick by holding the ALT key on a windows keyboard plugged into the iMac (wireless bluetooth mac keyboard wasnt responding) and formatted the disc accordingly.
Installed High Sierra and back to normal....
Thx again for all your help... next time i wont try and be such a smart ass

just want to knew what the most reason you want to install ubuntu.. Both are osx and ubuntu are unix variant anyway.. If just pure to code, homebrew all the way.

 

[cram501]

It wasn't stupid at all. Play with it, figure it out, f' it up.... That is where the fun is. You should always be able to get it back to normal.

If nothing else, you got a view of Ubuntu and learned how to create and install MacOs from a USB device.

 

[wardie]

You should always be able to get it back to normal.

To be fair, I’ve bricked a few things with dodgy firmware updates in the past... maybe “should” being the operative word.

 

[Shiro_Simba]

To be fair, I’ve bricked a few things with dodgy firmware updates in the past... maybe “should” being the operative word.

Installing software like an Os will not brick hardware. Now installing firmware ...... especially custom , good luck , play with it on PC motherboards that are build for it , and sort dual bios etc.... but anything else, playing with

 

[EugW]

Off topic but with Ubuntu 18.04, did the settings work properly for you?

For my MacBook4,1 in Ubuntu 18.04, when I launch the settings, it takes literally one minute to load. In Ubuntu 17, it took all of 5 seconds.

Since 17 is no longer being updated, I am thinking of downgrading to Ubuntu 16.04 just because of this. Everything else seems to work fine in 18.04, but trying to adjust anything in the settings makes me want to rip my hair out.