Making bootable USB for yosemite

[letquyen]

I have read instructions to make the bootable USB and according to what I understand, I need to have the installer app in the application folder. I can’t find it there and my MacBook Air has different OS, I wonder if what installer should I get and where to find it? I am new to Mac and learning, please help, thanks.

 

[MacInWin]

What model is the MacBookAir (MBA)? What version macOS is on it now? You cannot install on the MBA a version of the OS that is older than what originally came on the MBA.

You normally would download the installer from Apple. Typically, it ends up in the Applications folder, if it was downloaded as part of an upgrade/update from Apple. However, if you download it directly, not as part of the upgrade/update process, it goes to where you told it to go, or the default download location you may have set.

 

[ferrarr]

Here is where you can get Mac OS X/OS X/macOS versions,

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com

 

[Rod]

So apart from the questions above, can we assume you want to roll back your current Operating System to Yosemite?
The primary reason to create a Bootable macOS installer on a USB stick is to erase the Macintosh HD thereby allowing you to install an earlier macOS.
No, you will not find the macOS installer in your Applications Folder because it erases itself after use.
You must download a fresh copy from the App Store but you will not find it by searching on the App Store, you need a link as provided by ferrarr in post #3.
Lastly, but most importantly you must have a complete copy of all of your data to restore to the device after the "new" macOS is installed eg. a Time Machine backup.

The real question is why do you want to return to an earlier OS?

 

[letquyen]

So apart from the questions above, can we assume you want to roll back your current Operating System to Yosemite?
The primary reason to create a Bootable macOS installer on a USB stick is to erase the Macintosh HD thereby allowing you to install an earlier macOS.
No, you will not find the macOS installer in your Applications Folder because it erases itself after use.
You must download a fresh copy from the App Store but you will not find it by searching on the App Store, you need a link as provided by ferrarr in post #3.
Lastly, but most importantly you must have a complete copy of all of your data to restore to the device after the "new" macOS is installed eg. a Time Machine backup.

The real question is why do you want to return to an earlier OS?

I got a macbook air and a macbook pro. My macbook pro, the previous owner erased it and I can't install the OS using wifi. I have to use the USB to install the OS. I am new to mac so I thought it would be safe if I install the Yosemite OS since it booted into disk utility with option to install Yosemite. It's 2010 macbook pro and I can't use my apple ID to download the OS online. I would love to get newer OS if it would work with it, thanks.

 

[Rod]

Okay, two questions, why cant you use WiFi to restore Yosemite, what happens when you try to use WiFi? Can you use a LAN cable instead?
If the device boots into anything it should be the Recovery Partition not Disk Utility. Where it says reinstall MacOS Yosemite, if you choose that it should ask for a WiFi network which just requires you to choose one and put in the password.
Why can't you use your Apple ID to download Yosemite online? I'm assuming you mean on your MacBook Air.

 

[MacInWin]

I am new to mac so I thought it would be safe if I install the Yosemite OS since it booted into disk utility with option to install Yosemite.

In addition to the questions from Rod, what is the "it" in "since it booted into disk utility?" The MacBook Air, or the MacBook Pro? Can you give us a clear explanation of what it is you actually have? What Mac(s) and what version of macOS on each?

Normally, the best way to proceed is to install over the Internet, but you can you cannot use Wifi for that, so the USB may be the only way to get the MBP going, but to be able to help, we need to know exactly what you have and can use.

 

[letquyen]

Okay, two questions, why cant you use WiFi to restore Yosemite, what happens when you try to use WiFi? Can you use a LAN cable instead?
If the device boots into anything it should be the Recovery Partition not Disk Utility. Where it says reinstall MacOS Yosemite, if you choose that it should ask for a WiFi network which just requires you to choose one and put in the password.
Why can't you use your Apple ID to download Yosemite online? I'm assuming you mean on your MacBook Air.

I put my apple id and password and it said incorrect apple id or password. My apple id and password works well on phones, ipads... I know it's correct. I still got the confirmation on my phone when I tried to sign in. I think the 2 steps verification is the problem. I managed to make the bootable USB and I got my Macbook pro set up fine. My macbook air is running Big Sur and it's good.

 

[Rod]

Well done. My concern is that the previous owner did not follow the steps for;

What to do before you sell, give away, or trade in your Mac​

What to do before you sell, give away, trade in, or recycle your Mac

Reset your Mac to factory settings to prepare it for a new owner.

support.apple.com

If you read the above link you will see that everything Apple needs to be signed out of by the previous user.
If this is not done it can cause problems down the line. Hopefully you erased the device from the USB installer before installing Yosemite. If so that will fix most issues but if you still cannot sign in to iCloud or the App Store on the MacBook Pro this is the reason.

The previous owner can fix this my going to Apple ID Select Devices and Remove from my account.