Upgrading to Big Sur from Yosemite on a supposedly compatible machine

SGP4Jonah wrote:

I have been trying to download Big Sur for a couple of weeks per Apple's recommendation due to security issues with Yosemite not allowing me to log in to certain websites. I am logged in with my Apple id. When I click get on the download screen provided by Apple I am asked to sign in again. That sign in screen will not accept the very same password I used to sign in to begin with. I have changed it multiple times now but all that happens is it starts over again with me logging in with the new password I just created and so I am just going around in circles.

Is this a common/known issue and are there any solutions other than buying a new computer?

thanks!

Yosemite to Big Sur is too big a jump.. you are woefully behind. You do not clarify your exact Mac...for compatibility(?)

It never pays to get too far behind in the macOS or Hardware.

Stair step your way up to at least El Captain if not High Sierra...baby steps along the way always makes the transition easier— a lot has changed from the last update Yosemite 10.10.5.

The older macOS installer backups on this server:

https://support.apple.com/en-us/HT211683

verify you are using the Safari browser to download/initiate the macOS links.

To buy a new computer or not would be your decision alone to make...I have no input there.

Agree with pervious posting and would suggest the same.

High Sierra maybe a less drastic jump plus it may or may not include a drive conversion from HFS Journaled / GUID to the newer version of APFS / GUID Partition Map.

It may also install a newer Boot ROM that is needed for High Sierra to understand the new APFS format which is newer versions of macOS

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence

Make Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS

Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina, Big Sur & Monterey supports only 64 bit and there is no workaround.

Suggest using Go64 to find 32 bit application before attempting the upGrade. Some or many of the Application already installed may required update or upGrades to 64 Bit Versions.

Are there any AntiVirus, Disk Cleaner, Optimizers, Un-installers, etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal  operation of the OS and may even Corrupt the OS requiring a Reinstallation

I am on El Capitan, how can I update to each OS? Can't find on App store

If you follow the Link @ leroydouglas supplied ir for that matter the link from P. Phillips How to get old versions of macOS