Downgrading my OS failed and now I cannot access my Mac. How do I solve?

martimz wrote:

Hi PRP_53

, thanks a lot for your response.

Sorry if I split hairs but is it implied the Bootable Installer was made onto the Pendrive ?

Yes, I put the bootable Installer into my pendrive following this link: Create a bootable installer for macOS - Apple Support. However, I failed to complete step 6 of the section "Any other Mac", as I didn't realise that my Mac had a T2 Security Chip, as you and Barney-15E pointed out. So probably I didn't set my Mac to allow booting from external or removable media. Apparently I cannot do it anymore, as I deleted all my computer's data (i.e. the Mac volume). So I'm afraid I cannot continue your tutorial to downgrade the computer OS.

When I press "option" during the restart process, a button “install macOS Ventura” appears. But then it goes to the internet recovery again, yielding the same old -1008F error as usual :(

Yes I think we had already figured this out but did not what the hammer this home on you.

Have the computer evaluated by the Professionals who have the Special Hardware Software and Expertise to diagnose the issue and offer possible solutions

Make an Appointment at the Apple Genius Bar or call 1 800 MyApple and have them evaluate the computer

1. User wrote " I downloaded the Ventura installer and put it in a pen drive "

Sorry if I split hairs but is it implied the Bootable Installer was made onto the Pendrive ?

Or was the Full Version you just downloaded of Ventura Dragged Onto the Pendrive ?

If the later of the two, that may be why the computer is booting in Internet Recovery Mode

This method will WIPE ALL Data and there is No DATA Recovery - Period.

>> Only works on Intel Based Apple Computer which this is computer is Intel <<

To perform this action will require booting from a Bootable Installer. 

The Bootable Installer can Only be performed on an Apple Computer 

This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer.

Example : Bootable Installer of Ventura would have to be done on a computer that Qualifies to run Ventura.

Extra Special Notation regarding the Touch ID equipped Apple Computer.

 About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 

Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.

Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 

It will present options >> Disk Utilities >> View >> View ALL attached Drives. 

Choose the Upper Most Drive ( not the volumes indented and list below ).

The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map.

Once that is done >> backup out of Disk Utilities and choose install macOS. 

Follow the prompts and it may automatically reboot several time. 

Upon a final reboot - Setup Assist will present with the newer version of macOS.

You can use Setup Asset and point it to the Time Machine Backup Drive. This is a One Time offer. Thereafter you will need to use Migration Assist 

I have recently updated my MacBook Pro (13-inch, 2018, ThumderBolt 3 Ports, Intel Core i5 processor) from Monterey to Sonoma. But then my Mac became slow and I decided to downgrade to the Ventura OS. I followed the steps of a well recommended 3min YouTube video

Recommended by who?

I did the back-up of my data

2. I downloaded the Ventura installer and put it in a pen drive

3. I pressed command+R to restart the computer in recovery mode

4. I chose "Options"

5. I went to "Disk Utility" and erased my system volume (i.e. I have deleted all the computer's data).

If that is what the video recommended, I would question the intelligence of all that recommended it.

Before erasing the drive you should ensure you have a method of booting up the Mac once it is erased. Depending on Internet Recovery after the fact is disastrous as you found.

You should have created a Bootable USB Installer and made sure your Mac could boot from it before erasing. Is that what you did in step 2, or did you just copy the installer app onto that drive? (yes, I didn't bother watching it).

However, after step 5, my Mac didn't restarted automatically as in the video and so I had to restarted it manually.

I don't know why they would want to restart the Mac if it was booted into Internet Recovery already. There is no reason and invites problems as you found.

This is where the trouble began. After restarting it with the pen drive with the Ventura installer plugged in, the computer went directly to internet recovery. After some minutes of loading, a globe with a warning exclamation sign appeared with the message "support.apple.com/mac/startup" and on the following line the error code "-1008F" (see image below). I lost access to my computer, just the recovery mode screen is available now.

You can't just install from a disk with the installer app on the drive. You must create a bootable USB Installer from which to boot. You also have a Mac with a T2 Chip, so you must first enable external boot from Startup Security Utility. I don't think you can do that, now. Your only hope is Recovery. Take your Mac to another network and try to get into Internet Recovery from there.

martimz wrote:

Hi everyone,

I have recently updated my MacBook Pro (13-inch, 2018, ThumderBolt 3 Ports, Intel Core i5 processor) from Monterey to Sonoma. But then my Mac became slow and I decided to downgrade to the Ventura OS. I followed the steps of a well recommended 3min YouTube video (https://www.youtube.com/watch?v=JyMhvOWz4Jw1. ) to downgrade my MacOS:

I did the back-up of my data

2. I downloaded the Ventura installer and put it in a pen drive

3. I pressed command+R to restart the computer in recovery mode

4. I chose "Options"

5. I went to "Disk Utility" and erased my system volume (i.e. I have deleted all the computer's data).

However, after step 5, my Mac didn't restarted automatically as in the video and so I had to restarted it manually. This is where the trouble began. After restarting it with the pen drive with the Ventura installer plugged in, the computer went directly to internet recovery. After some minutes of loading, a globe with a warning exclamation sign appeared with the message "support.apple.com/mac/startup" and on the following line the error code "-1008F" (see image below). I lost access to my computer, just the recovery mode screen is available now.

https://discussions.apple.com/content/attachment/bae4eebb-a92f-4e87-a1af-735b7729dc601.

I then tried every sort of repair with the information I found on the internet (including everything in support.apple.com/mac/startup), but the results always failed. Here is a list of the shortcuts I used to try entering different types of recovery modes, having the pen drive plugged in:

shift: ended in internet recovery mode and then in -1008F

2. command+R: ended in internet recovery mode

3. command+option+shift+R: ended in internet recovery mode and then in -1008F

4. command+optio+P+R: ended in internet recovery mode

5. option: a button to “install macOS Ventura” appeared!! But then went to the internet recovery again, yielding the same old -1008F error...

6. option+D (or just D): ended in internet recovery mode.

7.

Here is a list of shortcuts I tried with my backup drive plugged in instead of the pen drive:

option: internet recovery and then -1008F

8. option+R: folder with “?” mark! At least it is something different...

9. option+command+R: folder with “?” mark

10. option+command+shift+R: folder with “?” mark

11. command+R: internet recovery without asking Wi-Fi password! But then error -1008F again.

12.

I also tried these shortcut combinations (and kept failing) in alternative conditions, i.e.:

Trying to downgrade to Monterey instead of Ventura

13. Tried using my cellphone internet instead of my Wi-Fi

14. Deleted my computer from iCloud (to remove the auto-lock).

What I think is happening is that I've deleted all of my computer's data, even the data necessary to reinstall an old OS. I have no clue how to solve this issue. Does anyone have some ideas on what to do to revive my computer? Let me know if you need any additional information.

Thanks a lot in advance!

ref: If your Mac starts up to error -1008F - Apple Support