After Installing Tahoe I Can't Create Boot Images Of Older OS (Catalina)!

Question

Level 1

100 points

After Installing Tahoe I Can't Create Boot Images Of Older OS (Catalina)!

I have a MacBook Pro (2021) running Tahoe (26.0.1). I recently found an old Mac Mini from 2012 I'd forgotten about. It boots fine, but as it was my son's Mac (way back when) no-one remembers the password. So I figured I'd just wipe the OS and reinstall. Sadly, this is almost impossible now.

If I go to the App store and try to download Catalina (which is apparently the newest OS the old mini can run) the App store grays out the Get button and says it's not compatible with my MacBook Pro (duh).

If I follow the instructions that Apple provides to get an older OS manually (in this case Sierra) I can't make a bootable USB drive image using their instructions. Note: If you try to download anything newer than Sierra you get jumped to the App Store and fail just like Catalina, so Sierra is the "newest" old version you can directly download.

I've tried various things but nothing has worked.

Can someone point me to a RECENT set of instructions (since Tahoe came out) on how to make a usable, bootable, USB drive with Sierra? If I can get the Mini running on Sierra I hope to be able to use the "normal" process for upgrading to Catalina.

Right now the Mini boots, but none of the onboard update options work... Ugh!

Earlier Mac models

Posted on Oct 21, 2025 7:29 AM

Reply

Answer 1

Top-ranking reply

MadMacks Author

Level 1

100 points

Oct 22, 2025 6:45 AM in response to HWTech

"using Command + Option + R to access the online macOS 10.15 Catalina installer."

This worked! Thank you... After multiple reboots and updates the Mini is now booting fine using Catalina 10.15.7 and everything appears to be working just fine. I appreciate all the feedback!

Reply

Answer 2

HWTech

Level 9

68,198 points

Oct 21, 2025 8:40 AM in response to MadMacks

You can only create a bootable macOS USB installer on another Mac that is compatible with the installer you wish to create (the host Mac can currently be running any version of macOS). This means for a 2012 Mini that you will need access to another Mac from 2008 to mid-2020 in order to create a 10.11 El Capitan or 10.15 Catalina installer:

2012 to mid-2020 Catalina
Late-2009 to mid-2018 High Sierra
2008 to 2015 El Capitan

You can use the information in the following article to confirm compatibility:

https://eshop.macsales.com/guides/Mac_OS_X_Compatibility

Make sure to read the following Apple articles very carefully....especially the section for downloading & extracting the installer from the DMG file for the 10.12 & earlier versions:

How to download and install macOS - Apple Support

Create a bootable installer for macOS - Apple Support

Or as @Niel suggested, use Recovery Mode or better yet Internet Recovery Mode (Command + Option + R) which will bypass issues with local recovery mode if the file system is corrupt or the drive is failing.

FYI, more than likely the internal Hard Drive is worn out or even failing. That, or it is an issue with third party software...most likely an update or new download if the issue with the Mini occurred suddenly.

Reply

Answer 3

HWTech

Level 9

68,198 points

Oct 22, 2025 7:13 AM in response to MadMacks

MadMacks wrote:

"using Command + Option + R to access the online macOS 10.15 Catalina installer."

This worked! Thank you... After multiple reboots and updates the Mini is now booting fine using Catalina 10.15.7 and everything appears to be working just fine. I appreciate all the feedback!

Thanks for the update. Glad it all worked out.

Reply

Answer 4

Niel

Community+ 2025

Level 10

740,801 points

Oct 21, 2025 7:33 AM in response to MadMacks

Restart the Mac mini with the Command and R keys held down and use the recovery system to reinstall the OS.

(261680)

Reply

Answer 5

HWTech

Level 9

68,198 points

Oct 21, 2025 5:11 PM in response to MadMacks

MadMacks wrote:

Doesn't work, or I should say, does work, but the recovery tool can't find the old image of the OS it is looking for, so i fails. Apparently, Apple has moved or dropped it from where "Recovery" is looking.

What is the exact error message you get? And for which OS is it attempting to load/install?

Try using Command + Option + R to access the online macOS 10.15 Catalina installer. Unfortunately some Macs may only boot to the online installer which originally shipped with the Mac from the factory. If it boots to the Catalina online installer, then there should be no problems assuming the internal Hard Drive is healthy & you have a good network & Internet connection...a wired Ethernet connection is best to avoid difficult to troubleshoot WiFi issues indicated by large negative error codes.

If the Hard Drive is healthy, then you should be able to access the local Recovery Mode on the internal Hard Drive using Command + R even with Filevault enabled.

With older systems you can create a new macOS admin user account where you can then download the Catalina installer so you can create a bootable USB installer. See the following article:

Restarting Setup Assistant to create Admin User - Apple Community

Reply

Answer 6

Oct 22, 2025 5:59 AM in response to MadMacks

MadMacks wrote:

I boot with Command-R and then click "Reinstall macOS". A "Install macOS High Sierra" screen comes up. I click "Continue" and after a few dozen seconds I get a "The recovery server could not be contacted."

Use Fix #3 for that:

https://mrmacintosh.com/how-to-fix-the-recovery-server-could-not-be-contacted-error-high-sierra-recovery-is-still-online-but-broken/

Reply

Answer 7

MadMacks Author

Level 1

100 points

Oct 21, 2025 2:04 PM in response to Niel

Doesn't work, or I should say, does work, but the recovery tool can't find the old image of the OS it is looking for, so i fails. Apparently, Apple has moved or dropped it from where "Recovery" is looking.

Reply

Answer 8

MadMacks Author

Level 1

100 points

Oct 21, 2025 2:09 PM in response to HWTech

"You can only create a bootable macOS USB installer on another Mac that is compatible with the installer you wish to create (the host Mac can currently be running any version of macOS). This means for a 2012 Mini that you will need access to another Mac from 2008 to mid-2020 in order to create a 10.11 El Capitan or 10.15 Catalina installer"

LOL. You happen to have an old Mac laying around so I can do this. It's ridiculous (not you, the statement if it's from Apple docs) that Apple doesn't have a better solution. I can find articles telling me how to create a bootable image of the old OS if I'm running a Windows machine, so I guess I'll give that a try. But it's silly that there's not at least a method using Terminal that works. So I think there has to be away to do it, just not using Apples "canned" way.

Reply

Answer 9

Oct 22, 2025 4:07 AM in response to MadMacks

The following might be a way to reset the admin etc passwords.

Here’s a link https://www.techbout.com/reset-password-on-mac-40802/ but the following are screen shots, if you prefer.

---------------

I tried on an Imac running Mojave and got to the screen to change the passwords on all accounts but I did not follow through resetting.

Reply

Answer 10

MadMacks Author

Level 1

100 points

Oct 22, 2025 4:32 AM in response to HWTech

I boot with Command-R and then click "Reinstall macOS". A "Install macOS High Sierra" screen comes up. I click "Continue" and after a few dozen seconds I get a "The recovery server could not be contacted." message. Note: I am connected to my network via Wifi before I start this process.As I can see several Wifi networks (all mine) I'm pretty sure it's not a Wifi issue. But I will use a wired connection to try as well, just in case...

Reply