I'm following the steps of installing an older software version (I have an old macbook pro from 2012), but I'm getting the message that the file is corrupted, so it won't start the installation. Any help here?
MacBook Pro 13″, macOS 10.12
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
The best possible version this computer may qualify to tun is Catalina macOS 10.15 and nothing newer.
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
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
The best possible version this computer may qualify to tun is Catalina macOS 10.15 and nothing newer.
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
To downgrade from Catalina to Mojave will require >>> Revert to Previous Working macOS <<<
Or
The Below instruction will Wipe ALL DATA including all applications , personal files and the Recovery Volume associate with this computer. There is No Recovery - period.
All Application, personal data etc will have to be reinstalled again.
To perform this action will require booting from a >>> Bootable Installer. <<<
This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Mojave would have to be done on a computer that Qualifies to run Mojave.
Once that is done read on for preparing the Destination computer
>> Only works on Intel Based Apple Computers.
Extra Special Notation regarding the Touch ID equipped Apple Computer.
About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting
1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.
2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive.
3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives.
4 - Choose the Upper Most Drive ( not the volumes indented and list below ).
5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map.
6 - Once that is done >> backup out of Disk Utilities and choose install macOS.
7 - Follow the prompts and it may automatically reboot several time.
8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.
Thnx, wish I had read that before, will downgrade from catalina again to mojave as my office won't work anymore ;). Downloading Catalina worked fine by the way, just not high sierra somehow. Thanks for the replies, will go back to another install process ;)
I can't downgrade I'm afraid, it says that this version is too old to install on this computer (probably because I upgraded too far first? What can I do? Install as new from backup? Will all my programs still be pre-installed then?
Welcome and do keep us updated on the progress - Tim permitting.
If additional questions arise - come on back and will our best to assist.
Thnx, will try that first option, the other one sounds complicated and far from perfect ;) I did make a time machine backup before I started this all, so option one should work.
Update to high sierra
