How can I downgrade my macOS?

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Level 1

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How can I downgrade my macOS?

Hello all,

I'm trying to setup a new-to-me mid 2012 MBP with Mojave. It came to me with a fresh install of Catalina. I quickly realized this machine cannot run Catalina. I also use iTunes and thus would like to move back to Mojave. After watching some videos and reading online it seemed simple enough. However I've hit an early snag.

Just downloading Mojave the MBP jumped straight to trying to install it. Reading online I should have been prompted first and clicked "no." But I never got the prompt. It's now stuck trying to "install update." I've quit the program as well as fully shut down the machine. When I go back to download it appears to have already been downloaded as it jumps straight to trying to install again. But if I search the machine I don't see the Mojave OS anywhere.

Any ideas?

[Re-Titled by Moderator]

MacBook Pro

Posted on Sep 2, 2022 4:13 PM

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Answer 1

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HWTech

Level 9

60,284 points

Sep 2, 2022 5:14 PM in response to Jason_Lsn

Yes, it can be annoying how the macOS installer work.

If your laptop can boot normally, then the macOS installer should be located within the Applications folder and be called something like "Install macOS Mojave". You can also use Spotlight to search for it. If the installer is no longer on the Mac, then download it again using the link in the following Apple article. If the installer is still within the Applications folder, then you can create a bootable macOS USB installer using the instructions in this Apple article:

How to create a bootable installer for macOS - Apple Support

If you have to download the installer again, then make sure to be present when the download is about to finish so you can quit the installer before it automatically begins installing & reboots the Mac.

It is also possible to download the installer using the command line by using the information in this article:

https://osxdaily.com/2020/04/13/how-download-full-macos-installer-terminal/

Personally I would add the "-d " option for "download only" just to be safe. So it should most likely make the final command:

softwareupdate  -d  --fetch-full-installer  --full-installer-version  10.14.6

You still need to follow the instructions to create a bootable macOS USB installer once the installer app has been downloaded.

I also highly recommend once you boot the macOS USB installer, that you launch Disk Utility. Within Disk Utility click "View" and select "Show All Devices" so that the physical drive appears on the left pane of Disk Utility. Select the physical drive which will usually be identified by the drive's make & model (or perhaps the USB chipset if an external drive) and erase it as GUID partition and APFS (top option). Quit Disk Utility and select "Reinstall macOS". Keep in mind this process destroys all data on the drive.

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Answer 2

HWTech

Level 9

60,284 points

Sep 7, 2022 5:34 PM in response to Jason_Lsn

Are you installing macOS to the USB stick or are you following the instructions in the Apple link to use the command line to create a bootable macOS USB installer? If you are installing the full macOS to the USB stick, then that will take a long time since USB sticks are extremely slow.

If you are using the command line to create the bootable USB installer, then it should not take too long to complete. If it takes more than about 30 minutes or so (an hour at most IIRC), then most likely the USB stick is bad or just really slow (neither is good). Or it may indicate you have some third party software installed which is interfering with the normal operation of macOS. You can try booting into Safe Mode to see if that helps since that should prevent the third party software from automatically launching during boot & login. If it is the USB stick, then try using another USB stick especially a different brand since the quality of USB sticks is extremely poor.

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Answer 3

HWTech

Level 9

60,284 points

Sep 7, 2022 6:26 PM in response to Jason_Lsn

Thanks for the extra information. My guess is the Apple hard drive is bad and needs replaced. There is also a chance the internal hard drive SATA Cable is also bad, but usually when this cable fails with a hard drive, the first part of the install goes well until the reboot when the second phase of the installation is performed. This cable has a high rate of failure on the MBPro 13" (mid-2012) non-Retina model. Replacing the hard drive with an SSD will likely solve the problem and provide a nice performance boost at the same time, although a bad hard drive SATA Cable is more likely to be noticed when using an SSD. Just be careful with SSDs since so many consumer SSDs these days are just low end budget economy models which can be just as slow as a hard drive. I find the Crucial MX500 SSD is a nice compromise on price & performance. Just stay away from the Crucial BX500 series SSD as that is a low end model which is as slow as a hard drive, plus it tends to overheat easily. In addition the BX500 has a high rate of failure.

You can try running the Apple Diagnostics to see if any hardware issues are detected. Unfortunately the diagnostics don't detect most drive failures. It is possible to check the health of the hard drive by creating & using a bootable Linux USB stick. I can provide instructions if interested.

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Answer 4

Jason_Lsn Author

Level 1

10 points

Sep 2, 2022 5:59 PM in response to HWTech

Thanks for the replay, here is where I sit now-

MBP will boot but seems to be running even slower if thats possible.
The Mojave installer did not end up in the applications folder as shown in all the tutorials I watched-
When searching for it, spotlight gives me nothing, Finder displays 4 items
- Mojave Day.jpg
- Mojave night.jpg
- mojave_whats_new.icns
- a folder called "com.apple.installassistant.Mojave.savedState Finder says this folder has 4kb of content clearly not 6 BG for the OS, within this folder are 2 items-
  - data.data
  - windows.plist

When I open the app store and try to re-download it. The download immediately finishes and it jumps straight to "installing update" and stalls there.

Is there a place to find where the partially downloaded OS is to delete and try to start the process over?

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Answer 5

HWTech

Level 9

60,284 points

Sep 2, 2022 6:19 PM in response to Jason_Lsn

If it is saying "installing update", then it sounds like you are installing a macOS update or patch and not downloading the full OS installer. If you want the full macOS Mojave installer, then use the link I provided earlier for creating a bootable macOS USB installer which includes links to download various macOS full installers.

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Answer 6

Jason_Lsn Author

Level 1

10 points

Sep 6, 2022 10:51 PM in response to HWTech

How long should the Mojave usb install take? I’m on a mid 2012 mbp with 2.9 processor and 8 go ram. Install has been going 2+ hours but the progress bar has been sitting at 2/3 for a solid hour+ without movement and the estimated time is “…”

Im using a brand new sandisk 32gb usb 3.0 drive if that makes a difference.

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Answer 7

Jason_Lsn Author

Level 1

10 points

Sep 7, 2022 5:51 PM in response to HWTech

I used terminal to create the bootable installer on the USB stick and per everything I read that went smoothly.

im now on my second pass trying to use the USB installer to install Mojave on the native 750 gb HDD. I followed all the instructions to reformat the drive and used the option key during restart to launch the installer. It’s a brand new sandisk ultra 3.0 USB. Fresh from Amazon and formatted prior to the installer install.

between attempts I ram first aid on the native drive and it came back clean. Re-formatted it again per the Apple guidelines. Extended journaled- guid partition scheme.

now 6+ hours into the second attempt and it appears the installer hung again in the same spot if the progress bar is accurate.

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Answer 8

Jason_Lsn Author

Level 1

10 points

Sep 7, 2022 6:49 PM in response to HWTech

Does a failing HDD or SATA cable lead to immediate failure or slow death?

I ask because when I got the mbp with Catalina it was incredibly slow. Like 30-60 second beach ball just hitting the Apple-about this mac, before the window actually pulled up. 10 second lag when typing in safari. I figured it was the OS and not a hardware failure.

my ultimate plan was to install Mojave to the native drive to by me time before an SSD. I have a Samsung evo 850 in my 2009 13” and planned to go that route again but I’ll look into the crucial.

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Answer 9

HWTech

Level 9

60,284 points

Sep 8, 2022 6:41 AM in response to Jason_Lsn

Most likely the original Apple hard drive is the culprit here especially for a laptop that old. I would first check the health of the hard drive as that is easy to do either with a bootable Linux USB stick or if macOS can be booted (internal or external), then DriveDx can be used instead to check the health of the drive. DriveDx is good at assessing the health of a hard drive for the common failures, but less so with SSDs since SSDs usually require a manual interpretation of the health report since not all "Warning" or "Failing" messages indicate a problem due to how SSDs work compared to a hard drive. It is actually very easy to get a fairly reliable assessment of the health of hard drives using these methods for the majority of hard drive failures.

Yes, the internal hard drive SATA Cable can cause those types of problems. The symptoms of a bad cable are actually quite varied.

If you wish to use Samsung, then that is fine. Samsung has been known to have some compatibility issues with some computers (especially older models). I would probably avoid the QVO series. I usually mention Crucial MX500 because they are usually a good option for most people and I know they work well with the majority of computers out there as well as for some other reasons.

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Answer 10

HWTech

Level 9

60,284 points

Sep 8, 2022 10:26 AM in response to Jason_Lsn

No, First Aid only checks for file system issues while DriveDx checks the hardware health report of a drive.

Even if First Aid says everything is "Ok" click "Show Details" and scroll back through the report to see if any unfixed errors are listed. Unfortunately the summary results for First Aid are not always accurate these days (why Apple?!?). I personally prefer to run First Aid on the hidden Container as that will also check all the other APFS volumes within that Container. Within Disk Utility you may need to click "View" and select "Show All Devices" before the hidden Container appears on the left pane of Disk Utility.

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