So as readers of my other thread will know, I have a brand new iMac. Not really relevant to my question below, but if anyone's curious, it's a 21 1/2 inch 4K with the i5 chip, 8 GB RAM, and 256 GB SSD. The old computer was backed up to an external HD, which I'm going to keep as an archive of my old files. I could buy a new external drive for backup, but I'm thinking of backing up to the cloud. There are plenty of cloud services to choose from. But I've been unable to find information about software to manage the backups. Apparently (according to a guy on Apple's phone support line) Time Machine requires a physical drive and won't work with a cloud drive. Is that true? What's a good backup program that works with a cloud service?