Trouble installing Big Sur

Try to install macOS Catalina first: App Store - macOS Catalina.

You indicate using macOS Mojave. Please know that macOS Catalina and later versions (including macOS Big Sur) are no longer compatible with 32-bit applications.

What is the partition type of your internal SSD? It should be GUID, if it is instead MBR (aka Master Boot Record), then APFS options will not be available. I haven't seen GUID listed in any of the pictures. You may need to click on the physical drive in order to see the partition type. Or you can launch the Terminal app and issue the following command:

diskutil  list  internal

FYI, you need to rotate your pictures on your iPhone/iPad. Unfortunately Apple's devices love to twist the pictures around no matter how carefully you try to hold the device in a neutral angle....very frustrating. Here is an Apple article with instructions for rotating pictures on your iPhone/iPad, I'm sure Android devices have a similar ability:

Crop, rotate, flip, or straighten photos and videos on iPhone - Apple Support

If you don't notice the photo is incorrectly oriented until you attach the picture, then just delete the picture from the forum editing window, edit the photon on the phone/tablet, and reattach.

Hello nebb1,

In Disk Utility, click the View icon to show all the devices:

You should then see elements (called volumes or containers) under the name of your internal drive. I believe this is those elements that can be converted. I write “I believe” because I don’t have any Mac on which I can actually test an APFS conversion.

I’m going to ask Mac experts to join this thread and provide guidance.

Hello nebb1,

1. In Finder, go to the Applications folder, delete the file “Install macOS Big Sur” and empty the Trash to recover storage space.
2. This article will show you how to find the 32-bit applications on your Mac. For each of them, go to the developer website to see if they offer a 64-bit version. Often they won’t state the 64-bit compatibility but will mention the compatibility with macOS Catalina or later, which is really what you need. Once macOS Catalina is installed, go to the developer website to download the 64-bit version of their app. Then delete the 32-bit version.

Hello nebb1,

Great! Now:

1. Start the Mac in recovery mode first: shut off the Mac, start the Mac pressing the command + R keys, keep pressing the keys until you see the recovery screen.
2. Open the Disk Utility.
3. Select "MHD" (just like in your screenshot.) If you don't see "MHD", click View > Show All Devices in the menu bar.
4. Right-click "MHD" and choose "Convert to APFS".

I recently faced a similar challenge to update two 15" Late-2015-class MBPs running El Capitan to something that would allow the use of newer browsers. If it may be of use, can do a writeup of the steps taken, end result was success on both.

Hello nebb1,

Please see the reply from @leroydouglas in this discussion: This volume is not formatted as APFS - Apple Community. It offers 2 ways to get around the issue.

nebb1 wrote:

Yes did that, see image, all I got from the right click was "unmount MHD". What should I do now please?

https://discussions.apple.com/content/attachment/b39fbc4a-24e7-4fdd-8aa7-bd2c63ee2290

Hello nebb1,

I may have misled you. I thought it would be prudent to start the Mac in recovery mode to convert the disk but this functionality might not be available in recovery mode.

Restart your Mac in normal mode and try to convert the disk. “Convert APFS” should also be available in the Edit menu (in the menu bar.)

Hello nebb1,

Thanks for trying. I went back to the answer from @leroydouglas and looked at the links, especially the questions.answers in this article.

Try doing it this way:

1. Start the Mac in recovery mode first: shut off the Mac, start the Mac pressing the command + R keys, keep pressing the keys until you see the recovery screen.
2. Open the Disk Utility.
3. Select "MHD" (just like in your screenshot.) If you don't see "MHD", click View > Show All Devices in the menu bar.
4. Right-click "MHD" and choose "Unmount MHD" (just like you saw in a previous screenshot).
5. In the menu bar, click Edit and you should see “Convert to APFS” not grayed out.

Click on the 3 dots, click on the mointain icon, choose your pic, then click on a Reply...

I am sensing a degree of worry over doing this which makes me wonder if you have a complete backup of your internal drive? That should be #1 on your list of steps.

Hello nebb1,

Have you made any progress? If you are stuck, could you show where?