How to upgrade from an Early 2011 Mac OS X 10.7.5 to 10.8?

[bjigyasa]

Hello.
I'm trying to restore my Early 2011 Mac Pro OS X 10.7.5 to the latest OS. I've read https://www.imore.com/restoring-high-sierra-older-mac-tougher-you-think and realise I need to upgrade to OSX 10.8 first.
I had done an internet recovery to reinstall the OS which was 10.7.5. However, I dont see any of the older os x in my App Store Purchases. Now every time I try to use App Store for downloading El Capitan or Mojave, the app store keeps throwing 'we could not complete your purchase: unknown error". I've tried resetting passwords of AppStore & Itunes, cleared cache & cookies, restarting etc. Nothing works.
Could someone please guide how I can upgrade from 10.7.5 to 10.8 (without having any of the older os x under my App Store Purchase) so I can finally upgrade to the latest OS? Many Thanks

 

[pkcable]

Try this....

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://support.apple.com/en-us/HT206886

Then this....

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://www.apple.com/macos/how-to-upgrade/[/FONT][SUB][SUP]
[/SUP][/SUB][/FONT]

 

[bjigyasa]

Thank you for your reply.

These were some of the first things I tried. I did it again and this is where every time I get the error 'We could not complete your purchase: Unknown error'. I've tried multiple things to fix this error starting from checking for updates within App Store & Itunes but the system always shows the app is up to date. My current App Store is Version 1.1.2 (92.10) and ITunes is 12.2.2.25. I believe the only way to update these apps is by updating the OS X but I'm unable to update the OS X via Apple apps because of outdated apps may be. Some websites suggested changing Apple ID passwords, clearing cache & cookies & rebooting. Nothing works. I even tried downloading some of the other In App Purchases like Word & the error throws up again. I'm stuck. Attaching the screenshot for your reference.

 

[pkcable]

I read on one of those support articles that another option for upgrading the OS, was to take your device to an Apple store and have THEM do it. Worth a shot?

 

[EdwinG]

If you have access to another Mac, you might want to try to download the installer with that and transfer it manually.