Keeping files on Time Machine, if deleted from the iMac?
I'm getting a smaller SSD drive (512GB) on a refurbished iMac than my current 1TB drive on the old Mac, which has already used up over 512GB on its internal drive. I have a 2TB external drive that is for Time Machine backups. I'll need to delete files from the current Mac to not have the newer iMac maxed out from new. The question is, how do I preserve those files on the Time Machine drive with the new Mac connected, so that it won't delete them on the first back up operation?
Thank you.
iMac 27″, macOS 10.13