Downgrade MB Pro (2015 model) from Monterey to Mojave

[Dr. McKay]

For several reasons, I need to install Mojave on my Macbook Pro 2015. It's running Monterey at the moment, the installed OS on purchase was High Sierre so Mojave should run without problems.

I have the installer file for Mojave and I have tried to make a bootable USB key using the method on Apple's website, using the terminal
sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/Mojave
In this case, I have erased my USB key, formatted it in Mac OS Extended and named the volume Mojave.

I can run the script just fine, the bootable USB is created (did this on my imac) but when I then put the USB stick in the MB Pro, I can boot up from it, but when I try to run the installer, it says that the installer is damaged and cannot be used.

I have tried to redownload the Mojave installer from the App Store (from within Monterey) but I get an error message just before the download ends and the installer is nowhere to be found.
Is there a way to download the Mojave from somewhere else as the one that I have is apparently not working...

 

[Xde]

If your system is Catalina or higher, did you try within the Terminal?
softwareupdate --fetch-full-installer --full-installer-version 10.14.6

Another way could be the tool from Dosdude

 

[Grumpus]

Perhaps you should try a different USB stick, 8 GB or greater in size, along with possibly waiting a bit and trying again to download via the App Store.

The dosdude1 macOS Mojave Patcher app can download a Mojave installer from Apple's servers, bypassing the store. After downloading it, double-click the .dmg. Then, right-click macOS Mojave Patcher.app and select Open to open it (double-clicking it may fail, saying it's from an unknown developer). After the app starts, click on Tools in the menu bar and select Download macOS Mojave. When the download completes, the Mojave installer should be in /Applications. At that point, you can exit the patcher app and run createinstallmedia to make your installation USB.

 

[Dr. McKay]

@Grumpus
I have tried a 8Gb, 32Gb and a 128Gb USB stick, all USB3, all with the same error.
But I just thought of something : I might try to do a reinstall of the initial OS via the internet, restoring the original OS as it were, and try and upgrade to Mojave from there.

If that doesn't work, I'll try your suggestion.
Thanks !

 

[Dr. McKay]

If your system is Catalina or higher, did you try within the Terminal?
softwareupdate --fetch-full-installer --full-installer-version 10.14.6

Another way could be the tool from Dosdude

Yep, tried that, got an error message in the terminal saying that the download failed...

 

[Grumpus]

I have tried a 8Gb, 32Gb and a 128Gb USB stick, all USB3, all with the same error.
But I just thought of something : I might try to do a reinstall of the initial OS via the internet, restoring the original OS as it were, and try and upgrade to Mojave from there.

If that doesn't work, I'll try your suggestion.
Thanks !

Well, fingers crossed, but the Monterey installation will have "upgraded" both the computer's firmware and its recovery partition, so you may find that Monterey is the oldest you'll be able to install from Recovery (but I'd be happy to be wrong!).

EDIT: I should explain that this happened to me and others, but it's not clear (to me, at least) if the problem happens only with Macs with T2 chips. Also, it's really not reasonable that all of your attempts to download Mojave should be failing. Apple's System Status page isn't reporting any current outages. If your download attempts continue to fail, then maybe something's going on with your network.

 

[Dr. McKay]

I did a restore of the original OS over the internet (back to factory, as it were) and it worked. To my surprise, it was El Capitan (I'm starting to doubt now what was on the Mac when I bought it, thought it was Sierra or High Sierra).
Anyway, it worked, upgraded to Mojave from there, no problem.
Phew !

Thanks for the feedback !

 

[Dr. McKay]

Little problem : I've got the Mojave Install dmg in my iMac's Trash but I can't empty the trash because it says the file is in use.
Now, I have tried holding the Option key while emptying the trash, didn't work. Did a disk check with Disk Utility, didn't work. Ran Onyx to check and cleanup the disk, didn't work. Tried booting in safe mode, didn't work. Tried the terminal with sudo rm , didn't work.

I'm out of options. Any suggestions ?

 

[Grumpus]

Close any instances of Terminal.app that are running. Then go to System Preferences -> Security & Privacy. In the left pane, scroll down until you see Full Disk Access and left-click it to select it. In the resulting pane on the right, find Terminal.app and check the box beside it. Now start Terminal.app again and run "sudo rm -f ~/.Trash/FN" where FN is the name of the undeleteable file. If the rm fails, please run "sudo ls -lA@ ~/.Trash" and "sudo lsof | grep -i FN, where FN is the name of the undeleteable file, then post the results.

 

[Dr. McKay]

sudo ls -lA@ ~/.Trash
Result = 0

sudo lsof | grep -i
Nothing happens...

Also tried Maccleaner full version, trash emptying failed...

Edit : when I right-click on the file in the trash, and 'show package contents', I get two folders Contents/SharedSupport/InstallESD.dmg
When I try the sudo rm -R command it says

override rw-r--r-- root/wheel restricted for /Users/myname/Library/Mobile Documents/com~apple~CloudDocs/.Trash/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg? y

After entering 'y', I get :
rm: /Users/myname/Library/Mobile Documents/com~apple~CloudDocs/.Trash/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg: Operation not permitted
rm: /Users/myname/Library/Mobile Documents/com~apple~CloudDocs/.Trash/Install macOS Mojave.app/Contents/SharedSupport: Directory not empty
rm: /Users/myname/Library/Mobile Documents/com~apple~CloudDocs/.Trash/Install macOS Mojave.app/Contents: Directory not empty
rm: /Users/myname/Library/Mobile Documents/com~apple~CloudDocs/.Trash/Install macOS Mojave.app: Directory not empty

I've tried to set the permissions for Install ESD.dmg to read & write for all but that's not permitted...

 

[Grumpus]

I'm guessing you have iCloud set up to store your Documents and Desktop. Maybe it's not finished uploading? I don't use that iCloud option and don't have enough cloud storage to turn it on to see if ~/.Trash is stored in the cloud or not. If it is, that seems to me to be an unfortunate design choice, but as I said I don't have enough cloud storage to experiment.

 

[Dr. McKay]

I've got 2Tb of iCloud storage, I find it very useful for when I switch between my iMac and Macbook, keeps everything in sync without hassle.
Except for now, don't know what could have caused the problem. I had the Mojave install .dmg on my desktop for a while and I guess I must have deleted it before the upload to iCloud was complete (5.5Gb takes a while to upload, after all, even on a fast internet connection).

Question is, how do I solve the problem...

 

[Grumpus]

Can you drag the file from the Trash back to the Desktop?

 

[Dr. McKay]

Yes, have done that. That empties the Trash, of course. When I try to delete the file directly from the desktop (alt-command-delete) I get the same message, cannot be deleted.
Trying to change the permissions doesn't do anything. I have tried almost anything.

Could returning to a previous TM backup work ? The thing is, I'm afraid I might lose some other files as I uploaded some extra stuff from my MB Pro to iCloud before wiping it clean round on the same day I messed around with that Mojave .dmg...

 

[Grumpus]

I would guess that trying to drag it from the Desktop to somewhere not synced by iCloud would fail in the same way, but I guess you can't know without trying. Short of temporarily turning off iCloud syncing for your Desktop I don't have any other ideas.

 

[Dr. McKay]

I'll experiment some more...

 

[Dr. McKay]

Looked for solutions on the net, really looked everywhere, I get the same 'solutions' everywhere (which don't work)..

Tried this today...
Using the terminal, tried again to delete the DMG on my desktop :

MyMacesktop myname$ sudo rm -R /Users/myname/Desktop/Install\ macOS\ Mojave.app
Password:
override rw-r--r-- root/wheel restricted for /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg? y
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg: Operation not permitted
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport: Directory not empty
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents: Directory not empty
rm: /Users/myname/Desktop/Install macOS Mojave.app: Directory not empty

Then I opened the package contents and dragged the file that just won't be deleted after the sudo rm -R command :

MyMacesktop myname$ sudo rm -R /Users/myname/Desktop/Install\ macOS\ Mojave.app/Contents/SharedSupport/InstallESD.dmg
override rw-r--r-- root/wheel restricted for /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg? y
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg: Operation not permitted
MyMacesktop myname$

I cannot change the permissions either, not allowed.
A bit hesitant to try and turn off iCloud syncing because I then get the message that every synced file on my computer will be deleted, but will still be available in the cloud.
However, suppose something goes wrong and somehow everything gets wiped in my iCloud as well, I would be truyl up sh*t creek without a paddle...

Sigh, I guess the only thing left to do is to reformat the mac and reinstall from a Time Machine backup, from before the stubborn disk image appeared on my desktop. Or just learn to live with the fact that that DMG file will be there until the end of time...

 

[Grumpus]

Have you tried this?

$ sudo xattr -rc ~/Desktop/Install\ macOS\ Mojave.app $ sudo rm -rf ~/Desktop/Install\ macOS\ Mojave.app

You could call Apple support, if for no other reason than to ask if they advise temporarily turning off iCloud syncing.

Your experience has convinced me to never sync Documents & Desktop to the cloud.

 

[chrfr]

Looked for solutions on the net, really looked everywhere, I get the same 'solutions' everywhere (which don't work)..

Tried this today...
Using the terminal, tried again to delete the DMG on my desktop :

MyMacesktop myname$ sudo rm -R /Users/myname/Desktop/Install\ macOS\ Mojave.app
Password:
override rw-r--r-- root/wheel restricted for /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg? y
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg: Operation not permitted
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport: Directory not empty
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents: Directory not empty
rm: /Users/myname/Desktop/Install macOS Mojave.app: Directory not empty

Then I opened the package contents and dragged the file that just won't be deleted after the sudo rm -R command :

MyMacesktop myname$ sudo rm -R /Users/myname/Desktop/Install\ macOS\ Mojave.app/Contents/SharedSupport/InstallESD.dmg
override rw-r--r-- root/wheel restricted for /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg? y
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg: Operation not permitted
MyMacesktop myname$

I cannot change the permissions either, not allowed.
A bit hesitant to try and turn off iCloud syncing because I then get the message that every synced file on my computer will be deleted, but will still be available in the cloud.
However, suppose something goes wrong and somehow everything gets wiped in my iCloud as well, I would be truyl up sh*t creek without a paddle...

Sigh, I guess the only thing left to do is to reformat the mac and reinstall from a Time Machine backup, from before the stubborn disk image appeared on my desktop. Or just learn to live with the fact that that DMG file will be there until the end of time...

After you create a USB drive, the process leaves a disk image mounted. Generally, this would go away after the computer is rebooted, but otherwise go to /Volumes and look for disk images you don't recognize, and eject them. Then try to delete the installer again.

 

[Dr. McKay]

Have you tried this?

$ sudo xattr -rc ~/Desktop/Install\ macOS\ Mojave.app $ sudo rm -rf ~/Desktop/Install\ macOS\ Mojave.app

You could call Apple support, if for no other reason than to ask if they advise temporarily turning off iCloud syncing.

Your experience has convinced me to never sync Documents & Desktop to the cloud.

First command : nothing happens.
Second command, same as before :
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport/InstallESD.dmg: Operation not permitted
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents/SharedSupport: Directory not empty
rm: /Users/myname/Desktop/Install macOS Mojave.app/Contents: Directory not empty
rm: /Users/myname/Desktop/Install macOS Mojave.app: Directory not empty

 

[Dr. McKay]

Restarted in recovery mode, csrutil disable via terminal, restarted, logged in, erased the file, restarted in recovery mode again, csrutil enable in Terminal, restarted, logged in...

All clear. Phew !

 

[carylee2002]

Seems like that so many people wants to go back to Mojave after upgrading. Must tell you something that Mojave is probably that good.

 

[sageman72]

As I have the same model and am considering doing the same thing, do you notice much difference after downgrading?

 

[Dr. McKay]

As I have the same model and am considering doing the same thing, do you notice much difference after downgrading?

No difference, doesn't run any better than with Monterey but I needed to downgrade to Mojave because I needed to be able to run 32-bit apps...

 

[sageman72]

Ok thanks, prob won't bother about it then