Hello,
What to do before you sell, give away, or trade in your Mac
I am not sure if you can use Time Machine to restore only macOS and Application without a user, but I think you can. The best way is to use the preloaded macOS, create a new user, and reinstall all applications from scratch, as you won't bring any clutter or outdated files from Time Machine to the new iMac.
You User folder needs to reside on the startup drive with macOS, as it cannot be run from an external. You can store your documents and Photos/Music/TV Library files on an external however.
Hope that helps.
C
Hi Cory, thanks for your reply. Basically the whole thing went 'tits up' (pardon my english). I explain hopefully to help others (replying in my sequence):
A) Old iMac HDD was formatted to be bootable. Downloaded new copy of Big Sur on new iMac with a view to installing on a 16GB USB drive BUT all instructions found to transfer the OS to the USB drive (with installer - to make it bootable) suggested using Terminal (and gave a sample of code to copy). Unfortunately Terminal would not allow me to type the password that was requested after running the code (seen threads of this happening to others too). Eventual found a program by 'Daddysoft' (or similar) that did the job. All worked but what effort!
B) Because I wanted to do a re-install (partial or otherwise) on a new SSD - Time Machine refused to run (presumably because the old backup was done from a diffenrent HDD). Fortunately all my apps are on an external drive (used with the old and new iMac) and so it was a matter of 'drag and drop' to copy from old external to new SSD (then run item to check it functions). Time consuming...
C) Bootable verion of 'old' Big Sur on external disc would not run as "security" on Big Sur on the new SSD would'nt allow - so no help! Anyway, old OS still sits on external drive along with the applications, and appears to co-exist quite happily with the SSD. Principal reason for keeping both SSD and HDD is wanting to keep my large library of photo work on the HDD whilst running the 'processing' software - Lightroom and Photoshop on the fast SSD (otherwise the library would swamp the 512GB SSD... It all works so far!!
Hindsight says I should have keep the OS on the original iMac and progressively updated from there and created new boot drive all within Time Machines 'known' environment. Oh well - if there's a next time I will try and remember all this experience....
Oh, finally, I found that my nice new download of Big Sur on the SSD, which ran so nice and smoothly, had 'removed' every single sub-mail box in Mac Mail that I had carefully used for my filing over the years - but at least it had the 'decency (ha ha) to put every one of the 18,000 filed emails into the standard 'Important' mailbox (so they were not lost). So I have happy months of work ahead of me to re-file these emails... Deep Joy!! (Pleanty of other threads posted by others bewailing the same problem - how can Apple let this sort of glitch happen????
