I'm writing this because of all the reviews I see complaining about the drive not showing up on their computer initially, saying "it doesn't work right out of the box!" I often wonder if some of these people never even read the documentation before giving up. The included documentation for the drives is horrible, with only a Quick Start page that shows how to plug it in, but there is great info on Seagate's site that helps if you go look at it. There's also something else I found out that might be helpful, and I'll address that here. Once I've had it in use for a while I'll update this review for a more in-depth account of how well it works. I'll list my comments by issue:1) Drive not getting recognized.After seeing so many "it doesn't show up" comments, I was concerned when mine didn't show up on my iMac either. I followed the instructions on plugging it in (in sequence, which may or may not make a difference, but you gotta do it correctly just in case), and the first thing you have to do is decide which US Standard plug to slide onto the universal plug adapter; there are two that are almost identical, two-prong plugs; one has holes in the prongs and the other doesn't. Docs say nothing about which to use, so I went with the one with holes.The unit powered up and sounded like it was initializing, but it wouldn't get recognized by my Late 2017 iMac. Unplugging and restarting did nothing. I went to the online documentation and did the recommended check to see if Show Hard Drives was checked in Finder/Preferences/Show-Hard Drives. It was (which I already knew because my others show there, but just in case I needed to recycle the command...). That did no good. After a bit of thought, I decided I'd try the other plug, and that did the trick. USE THE PLUG WITH NO HOLES IN IT if using in the US!Once that was solved, it showed up and all looked good.2) Using with Time Machine on Mac.The info in the product description says the drive is ready to use with Time Machine, preformatted. The problem is, if you have Catalina or later, there is a new formatting called APFS that replaces xFat, and you will have to reformat to use with Time Machine. This is a simple process using Disc Utility, and it reformats quickly.Once I had that issue solved, I got Carbon Copy Cloner (trial version) and set up the tasks of copying my main hard drive (348.3 GB) and my 8 TB external drive to the new Seagate drive and let it go. The main drive was backed up in just over 47 minutes. Yeah, it's a tad noisy, but nothing that can't go on while working on the computer by any means unless you're maybe recording a YouTube video at the computer or something.The external drive, which had 6.58 TB of stuff on it took a little longer... 12 1/2 hours to be exact. Slow? I don't know, it's the first time I've copied a hard drive with that much stuff on it, but I set the task and left it alone and it was done in the morning. The image included here shows Carbon Copy's review page for the performed tasks.CAVIAT: you may need to use a program that allows the computer to work without shutting down after a period of inactivity. I use an app called "Amphetemine", which forces the computer to stay on in various circumstances that you can set. I set mine to remain on "as long as specified app is working" and chose Carbon Copy Cloner. Not sure you have to do this, but Amphetamine is a great app and I didn't want to take the chance of having to start over, so I used it, and it worked great.The noise some complain about could be other drives (I have the 12 TB version for desktop) or it may be a personal preference, but a drive in a plastic case like this with lots of air holes in it will make some noise, however I didn't find this "noisy" at all IMHO.So far, I'm impressed with Carbon Copy as well, but like the drive, I'm in my infancy with using it, so time will tell. I also have a 1 TB external I use for Time Machine, so instead of using this one for that, I will most likely also set up the drive to copy that drive so I have a backup of my Time Machine just in case. You can set Carbon Copy to copy whenever it detects a change in a drive, so once the initial copying is done, the lengthy copies are done, and it's only copying when things change.If you have issues with one of these drives not being recognized by your computer straight out of the box, FIRST make sure you have the correct US plug installed. THEN, make sure to reformat to APFS if you're running Catalina or later if you plan to use it for your Time Machine backups. At that point, so far in my experience, it's a great drive. I'm giving four stars only because of having to hunt down good documentation for the actually necessity for reformatting for the OSs, and for having NO information about the right plug to use. NO idea why the one with holes won't work, but it would be nice if they gave a heads-up on that.Once it's been working a while, I'll readdress this review.