Apple Support – How to Update to OS X Yosemite
I think you could be able to use the Mac App Store to update to High Sierra from there.
Attempt this:
- Empty the trash and remove the InstallMacOSX.dmg file that was previously downloaded.
- Select Software Update from the Apple menu . After installing any Snow Leopard updates that are available, restart your iMac.
- Download and upgrade to OS X El Capitan by clicking this link – Apple.
You should be ready to upgrade to High Sierra after the El Capitan upgrade is finished, I believe. - Download and update to macOS High Sierra by clicking this link – Apple.
Regretfully, I have no idea what the issue is in this instance and don’t know how to move forward at this time.
If you first delete the current download, you could try downloading 10.11 El Capitan again.
It’s possible that your initial plan to download Mountain Lion and start the upgrade from there was spot on.
I’m hoping that this will fix the problem.
You could try restarting the iMac in safe mode and letting it take care of housekeeping and cache cleaning.
Maybe try installing the software in safe mode and see if that works.
I appreciate all of your time, man. You took a great deal of time to assist me, and I sincerely appreciate it.
I’ll attempt to download Mountain Lion and see if that solves the problem. Once again, thank you. I’ll let you know if I manage to make something work.
Snow Leopard Upgrade
The Mac OS X Snow Leopard (10.6) is regarded as the final version that was primarily created without taking cues from iOS devices.
The short answer is that you can update to OS X Snow Leopard (10.6) if your Mac has an Intel processor and is currently running an older version of OS X.
You must identify the Mac model and processor type you own before determining whether to upgrade to Snow Leopard.
To begin with, find out if your Mac is compatible with OS X Snow Leopard’s minimal configuration requirements.
Your Mac might not be able to use all of the new features in Snow Leopard, even if it satisfies the system requirements.
Snow Leopard’s ability to distribute processes among several processors or processor cores thanks to Grand Central Dispatch greatly enhances Mac performance.
To utilize OpenCL with Snow Leopard, your Mac needs to have a compatible graphics chipset.
Manually Updating to High Sierra
You can update to High Sierra on any Apple computer that is newer.
The system prerequisites are identical to those of macOS Sierra.
If you’re looking to upgrade your current Mac, go to the APP STORE (seen below) and select UPDATES to download and install High Sierra.
Similar to earlier iterations, macOS High Sierra can only be downloaded via the internet.
A physical copy is not available for purchase in a retail setting.
After you upgrade, all of the installed apps on your computer will remain intact.
Nearly every program you have installed on your computer ought to function properly with macOS High Sierra.
Upgrading Snow Leopard
You must have an Intel-based Mac running Mac OS 10.5 or earlier with at least 1GB of RAM if you want to upgrade to Snow Leopard (OS 10.6). Snow Leopard will not run on a PowerPC processor.
Next, get the Apple Store’s Snow Leopard installation DVD.
To update Snow Leopard to OS 10.6.8, perform Software Update from the Apple Menu after installation.
Many people just upgrade their OS installation over the previous one, but I advise creating a full bootable backup beforehand in case something goes wrong (like a power outage during installation).
As an alternative, install Snow Leopard using the GUID option on an empty partition that has been formatted as Mac OS Extended (Journaled).
By pressing the OPTION key during startup, you can then boot up from Snow Leopard or your previous operating system.
Assuming you are running OS 10.6.8, you can upgrade FROM Snow Leopard.