How do I transfer all my backups from my old iMac’s Time Machine drive to my new iMac’s new Time Machine drive.

Thanks, PTP_53

can not be moved from 1 external drive to another external drive

Was this possible in the past? I think some years ago when a Time Machine external started to fail, I was able to replace it with a new one and transfer all the old backup information from the old to the new.

Put aside the existing older TM Backup Drive for Safe Keeping

How would I use it, say, to find and download a specific, earlier version of a file?

My old TM backup drive was working fine. It is a 2TB external, backing up, first, my 1TB 2017 Intel iMac and then my one-month-old 1TB M3 iMac. Curiously — to me — it was only about 60% full on the Intel iMac, but jumped to 95% full right away on the M3. (Can you hazard a guess as to why?) Ignorant of the “cannot be moved” prohibition you've explained, I bought a 4TB external to give Time Machine what I thought it needed in the way of more breathing room. (Now, of course, there is only about 530GB backing up from the new iMac to the 4TB drive.) Should I (assuming I can) go back to using the old backup drive until it fails and just let it delete old files as needed in the meantime?

Thanks.

Thanks, PRP-53 and Barney-15E. I'll keep the old Time Machine disk in a safe place and if I am ever desperate for at least one copy of the file, I'll dig down manually through the nested folders, even though it takes a very long time. For years and years, Apple touted Time Machine as the ultimate safety net for protecting multiple versions of files for retrieval. If they now had to prevent transfer from one external to another for security or stability reasons, they should've come up with a workaround so we could preserve those backuped versions and make them reasonably accessible.