Desperately need to remove Catalina and reinstall Mojave

You can revert but, only of you have a backup prior to the install. I ran foul of this problem created by Apple Inc. Eventually had to revert to a very old full backup as Catalina seems to block partial restores from previous OS versions. Good luck.

Thank you SO much @Scily98 I followed your procedure to the letter and it worked for me even when reverting back to El Capitan! My only note (for novices like me) is with the step “raised the volume” this means you click on the new SSD flash volume on the left, then choose “erase”, then rename Macintosh HD with OS Extended journaled, I kept the next box below that as the default. Thanks again you’ve totally saved my bacon!!!!

Hello not a stupid question. The Disk should be named “Macintosh HD” and the OS Extended Journal is the format of the disk. Usually a drop down under where you rename the disk. I’m not totally sure you will be given a format option if you are in the restore from time machine section so you may not need to worry about it.

First thing to check is if the disk is mounted in disk utility.

Just before we go to dire steps can I ask. Do you have a time machine of the original machine running the OS you want to keep using.

Not yet. I would love to be able to just go back to a backup from my external hard drive but at this point would settle for wiping everything and going back to a previous OS (preferably El Capitan, as that was the last OS I was running and everything worked beautifully). When I go into Restore mode though alas, I can only restore to Catalina.

So I followed apple’s instructions on making a bootable usb for El Capitan but now the only option in the startup disk utility is my hard drive. It apparently is not detecting the usb, even though disk utility and finder and everything else recognizes it.

Hi - I'm trying to do exactly what you did - revert to El Capitan from Catalina via Time Machine back up. I am getting stuck on the point where you delete the Macintosh and Macintosh HD and then rename an SSD that shows up? I have literally never done anything like this, but I knew I should be able to do a restore to a previous back up. This step is confusing and I want to make sure I understand. When you say to 'rename Macintosh HD with OS Extended journaled', can you explain what that means? What would the new name be? And if OS Extended is referring to something I need to use and it isn't the actual name - please direct me.

I'm sorry, I feel like this question must sound so stupid, but I am really not even at novice level. I am an idiot stuck with a bad decision - taking the chance to upgrade to Catalina when I shouldn't have. But truly thought I'd be 'ok' since I was supposed to be able to revert back to previous Time Machine back up. I've been now dealing with this for at least 9+ hours between yesterday and today. Hoping I don't have to stick with Catalina - it's awful, it's heating my machine when nothing is open, I've lost photos, I hate it. Any help - and as detailed as possible - would be so incredibly greatly appreciated!

Thank you so much! I got it to work and I am back to good El Capitan and THRILLED!

I realized I had two big confusion points - first, was understanding that the OS Extended Journal piece was a format selection, not part of the name. Thank you for that clarification! That helped a ton!

But then my second mistake was I didn't realize I needed to rename and select the format 'at the same time' I was erasing the disk. So I ended up erasing the disk without renaming it or selecting the format - or even noticing those fields, I guess. Once I realized my mistake, I went back to the disk and repeated the process correctly - renamed the disk Macintosh HD and selected the OS Extended Journal format and then selected Erase. I must have been completely missing or not paying attention to that area originally since I didn't know I had to do it all at same time as erasing. Once I saw it - the OS Extended Journal was right there on the format drop down list! And then it all went smoothly after that!

I have never been so happy and relieved all at once! I thought at one point I'd turned my laptop into a brick by erasing the disk wrong. Thank you, thank you, thank you! And also to KeithAnsel! You guys saved my butt! =)

Thank you so much!!! I just posted a reply above to Sclly98, which fleshes out what happened, kinda long so I won't repeat. But thanks to you and them, I got it to work and am now happily typing away on my perfectly restored El Capitan!!! You guys saved my butt!!! =)

I'm trying to go back to El Capitan from Catalina, I've followed the thread and done as instructed, but now my mac won't turn on it gets to image below.. :(

is it anything to do with the apple disk image? do I need to delete this too? any advice will be useful!

I, too, feel like Nine9. I'm an idiot stuck with a bad decision.

My question is, which drive do I delete? When I use the Show All Devices menu, which do I select?

Apple SSD SM0512F (at the very top) "PCI Internal Physical Disk"

or

Container disk2 (right below Apple SSD SM0512F) "APFS Container"

Thanks for all the great tips that everyone has posted. I am really not tech savvy when it comes to digging deep into the bowels of my Mac, so all the details matter to me. I will be reverting back to Yosemite. Gasp! Yes, my Mac is that old.

My Mac is really old :( so I have to install OX S Mountain Lion then install El Capitan, so I get to El Capitan and then try to restore my machine but I get the black apple logo and loading bar, I wait for at least 20-30 mins then go back to step one. My next move was manually installing my software but it turn out adobe software does work ( all of CS6 ) - I get an Error code 16

I wish I never download Catalina - dramatic as I sound but I cannot seem to get all the important software and cannot afford to switch to creative cloud at this state. Would you know how I can re install the application back on to my machine? I have the licences to these I bought them a while ago but it doesn't seem to link them up.

Yes I do have my time machine backup from 2016 on an external hard drive

After much frustration I called Apple support and they said it could be an issue with the adobe application I keep receiving the error code 16 for CS6 and Microsoft just doesn't work, I called Microsoft and they said if I'd had the software for a really long time there was a chance that applications may have an error due to all the upgrades it has had on my computer, and they tried to sell the 2019 version

-_-

I know I will need to invest in it at some stage, but was keen to buy myself time

However I can confirm my time backups are legit!

Every time I reached the stage where I re download El Captain and tried and restore from time machine it goes back to Catalina!

According to Apply My Mac book Pro is vintage! :( Stupid Catalina

Thanks so much for helping us all out with this issues. I've joined the band of idiots making bad decisions 2 days ago, and now I need to go back to downgrade from Catalina as some of the softwares I used for work are not compatible.

I've read everyone's posts and tried to put together all the steps and tips. But before I embark on this quest, I'd like to triple check that I got this right:

• First of all, I have a Time Machine Backup pre-Catalina on an external hard drive, and also a new backup made from Catalina which exlcludes the Apps and the System folders, just in case
• Then I have created the bootable installer onto an external device (in my case I'm using the same external hard drive where my back up is, which I have partitioned and formatted so it's a Mac OS Extended Journal format).
• At this point, I need to restart the machine in recovery mode
• Open Disk Utility
• Erase Macintosh HD and Macintosh HD - Data after changing their format to Mac OS Extended Journal by clicking on "-"
• Then select the new installer and click '+' to rename it as Macintosh HD
• Go back to restore from Time Machine

I hope I got the process right. Please let me know if I made any mistakes, and I apologise for the poor terminology.